As Sir Mark Sedwill prepares to leave a job he never asked for, he reflects on the highs and lows of being cabinet secretary

Sir Mark Sedwill is preparing to leave a job he never wanted in the first place. 

In the summer of 2018, when Jeremy Heywood, then cabinet secretary, took a leave of absence to undergo cancer treatment, Sedwill was already in what he calls “the job I spent 30 years qualifying myself for”. 

The long-term securocrat and former ambassador had been the UK’s national security adviser for just over a year when Theresa May asked him to step into Heywood’s shoes. When Heywood suddenly stood down, two weeks before his death in November 2018, Sedwill officially became his successor.  

The UK cabinet secretary, who is also head of the civil service, already wears two hats. By remaining national security adviser as well, Sedwill added a third. This eye-catching decision prompted much ink to be spilt by Whitehall watchers at the time – although, as Sedwill himself pointed out to CSW in an early 2019 interview, the cabinet secretary role has “been quite markedly different” over time, flexing to meet the needs of different administrations. 

Still, Sedwill’s career (see CV box below) could hardly have been more different to that of Heywood – an economist who built his Whitehall career in the Treasury and No.10, with a stint in investment banking. A former minister who remembers Sedwill as a promising young private secretary to foreign secretaries Robin Cook and Jack Straw, notes that he did not take a “conventional” civil service career path; another is at pains to point out he is now president of the ultra-discreet Special Forces Club, whose members include SAS members and spies. 

“I think I am a different kind of cab sec not because I was national security adviser, but because my entire career had prepared me to be national security adviser,” Sedwill says. “Inevitably, what I brought into the job of cabinet secretary is not [just] the last job, but my background and experience.” 

When he took over, Sedwill had worked alongside May for five years – first as Home Office perm sec while she was home secretary, then prime minister – and had become her trusted ally.  He says May knew what she was getting – and “I was unable to persuade her to not ask me to do it.”

Did he try? “I'm not going to get too far into that. But I've never made any secret of the fact that I took on the job because I was asked to, out of a sense of duty.” 

Ever the diplomat, he adds: “And of course, I should leave private the exchanges I had with the then-prime minister.” 

Speaking to CSW remotely from the wood-panelled grandeur of the Cabinet Office, Sedwill says he believed May “wanted someone to bring to the job, for this period, the background and experience that I had – in particular, in security policy and foreign policy and the Home Office”. 

Sedwill’s letter to Boris Johnson confirming his departure in late June said while the tripartite role had been right for the time of Brexit and the early response to Covid-19, that was no longer the case.

“It wasn't ever designed to be a permanent model and certainly not one that I would have expected to apply to my successor,” Sedwill says. 

“[Splitting the role] could have been this summer, it could have been a little bit later. But we concluded that with the government’s Covid response moving from the initial response – dealing with the acute public health crisis – into the recovery and renewal phase, that it was the right time to make the change.” 

The announcement that the NSA job would go to David Frost – a former FCO official and ambassador who became a special adviser to then-foreign secretary Johnson and then the UK’s lead Brexit negotiator – has been the source of some contention. May herself demanded to know why Sedwill was being replaced by a “political appointee with no proven expertise”. 

When questions about the appointment have arisen, Sedwill has pointed out that he is the first NSA since the job was formally created in 2010 to have led a major government home department, so Frost’s background is not extraordinary for the role. 

"Obviously, I think I'm the perfect fit for the job, because I'd always wanted to give it a shot"

But it is difficult to believe Sedwill’s CV did not make him a better national security adviser. He has certainly been well respected in that post; David Lidington, who was Cabinet Office minister at the time of the Novichok poisonings in Salisbury in March 2018, tells CSW the “unflappable” Sedwill “deserves a slice of the credit” for how the government handled the response. 

Sedwill says he’s “probably the worst person to ask” whether his experience changed the role for the better. “Obviously, I think I'm the perfect fit for the job, because I'd always wanted to give it a shot,” he says, laughing. 

“This job has changed over the years. Sometimes it's had more of an international focus and in my time, it had more of a blended international-domestic focus – of course, Brexit was the big issue of the time. At some point in the future, it might be right to have a national security adviser again with more of a domestic focus. 

“I think the job should reflect the priorities of the government and the prime minister of the day and the prime minister has decided, in choosing David Frost, the shape of the job he wants, the focus and the experience he wants bringing to it. And that's a perfectly sensible set of arrangements.” 

Sedwill always planned to move on when the jobs split, he adds. “It wouldn't really have made sense for me to go back to being the national security adviser and be up in the attic with a new cabinet secretary here.” 

Instead, he will lead a new G7 panel on global economic security – which, he recently told a committee of MPs, underscores the “entirely amicable” nature of his departure – and is in line for a life peerage. 

“It wouldn't really have made sense for me to go back to being the national security adviser and be up in the attic with a new cabinet secretary here” 

But Sedwill must have known how it would look when it emerged that he would receive almost £250,000 “in consideration of his employment position” when the time came. 

The cab sec tells CSW the payout is “standard”. “That is a calculation made by the experts for someone in my position for voluntary early retirement by agreement – that's essentially what I took. And then there is a compensation payment into the pension.” 

It is not, he stresses, a redundancy payment. “There's a distinction between the two. I know it’s a significant amount of money… But if I've been made redundant, actually it would have been more than that under the terms of the Civil Service Compensation Scheme. Significantly more than that.” 


Sedwill’s two-year stint as cabinet secretary has made up a fraction of his 30-year civil service career – but in his time at the helm he dealt with crises that his predecessors would have been unlucky to face during a decade in the post. 

The parliamentary chaos of Theresa May’s efforts to get her EU withdrawal deal passed – amid Brexiteers' sniping at civil servants – led to a change of prime minister, then the country’s third general election in five years. 

What felt, at one point, like it would be a (comparatively) quiet year in government after Johnson’s parliamentary majority got his Brexit deal passed was quickly subsumed by the coronavirus pandemic – probably the biggest peacetime crisis in a century. 

Sedwill says the response of civil and public servants to coronavirus has been “magnificent”. “I'm really proud of it. And I'm proud of it not just as the head of the service, but as a citizen," he says.

“Just look at what we did. Not a single person in this country failed to have the medical treatment they needed. Every single person who needed a ventilator got one. That is not true in every Western country."

He cites the furlough and business support schemes set up “in absolutely record time”; a programme to send food packages to those shielding during the outbreak; and support for socially-isolated people. 

"There will have to be questions about whether the right decisions were taken at the right time... Are there things we could have done better? Could we have had more preparations in place?"

Sedwill does acknowledge that when the inevitable public inquiry happens, “there will have to be questions about whether the right decisions were taken at the right time... Are there things we could have done better? Could we have had more preparations in place? Are there different decisions we could have taken? 

“But what I can tell you is that everyone involved, ministers and officials, was seeking to take the right decisions. They took the decisions for the right reasons, and they took them on the basis of the best evidence and expert advice – scientific advice and other advice – that they had at the time.” 


Sedwill has said before how proud he is when public servants come together and cross silos in a crisis – during not just Covid, but other major incidents too. But, as he recently told a committee of MPs, “turfy behaviours” quickly re-establish themselves.

“It is, of course, more complicated than this, but if we could bottle what we achieve when we're responding to a crisis – whether it's Salisbury, or whether it's planning for no deal [Brexit], or whether it's dealing with something like Covid – and apply that team spirit, that focus on impact, that collaborative effort, to all the rest of our work, just think what we could achieve,” he tells CSW

His own attempt to do that comes under the Fusion Doctrine – a set of structures to improve joined-up working in national security, which he has since attempted to implement across the wider civil service. 

He admits the “underlying concepts” for working collaboratively, focusing policy design on the delivery, and ensuring government has the capabilities in place are not particularly new. But he does believe Fusion could be an effective way to make them happen. 

It was Fusion that underpinned the government’s response to the Salisbury poisonings, for one, he says. “If you spoke to most people in the national security community, they would tell you it's been working well, and they would like to see it operate more effectively elsewhere in government.” 

And he says there has been some progress towards embedding the system elsewhere in government, where vertical hierarchies are clear but horizontal structures are “still not as strong”. 

Others have described Whitehall’s flaws in rather less flattering terms. Top No.10 spad Dominic Cummings – who arrived into Downing Street having already written thousands of words on civil service reform and is now at the heart of devising changes – has described the permanent civil service as an “idea for this history books” and said HR practices reward mediocrity and over-caution.  

Does Sedwill agree with Cummings’s criticisms? “Look, I don't think of them as criticisms. The civil service, like every other big institution, needs to modernise and reform; it always does.” 

Referring perhaps to Cummings’s 3,000-word blog calling for “misfits and weirdos” to work in government, Sedwill goes on: “Although I wouldn't express it the same way as Dominic Cummings, I also think the desire to ventilate more, to bring in more expertise into the civil service, is a good thing.  

“Although I wouldn't express it the same way as Dominic Cummings, I also think the desire to ventilate more, to bring in more expertise into the civil service, is a good thing" 

“He uses his own way of describing that. But it's fundamentally a good thing to bring in people with different experiences, different backgrounds, particularly people with knowledge of data and digital and science and so on.” 

Other areas of the Cummings critique where Sedwill sees merit include reducing turnover in top jobs and having more senior officials based outside London.  

But he acknowledges these are longstanding problems that successive governments have failed to change. Officials move posts to get pay rises not afforded to them in their current jobs, he says, so much so that there is a need for a fundamental review of pay and reward. Meanwhile, efforts to move senior roles out of the capital have long been hindered by “the gravitational pull of parliament and ministers” back to Whitehall. 

He set out some of his own thoughts on how the civil service might change in his last major speech as a civil servant at the Blavatnik School of Government. He set out a two-pronged approach to change how departments work: integrated policymaking in priority areas though an approach based on the Fusion Doctrine, and a new performance framework to monitor performance in other areas.

Attempts to implement the government's plans to "level up" the country are " unlikely to prosper" without changes, he said, which should also include "a fundamental review of pay, progression, of pensions" across the civil service to encourage officials to stay in posts and develop deep expertise in policy areas.

Does he think Cummings’s aggressive rhetoric indicates the tune will actually change this time? 

“The nature of the political debate is that things are expressed more vividly than a civil servant, including a cabinet secretary, is going to express them,” he said. “Take a step back and although I express things in less vivid language than a politician or a special adviser, for the vast majority of civil servants, these shifts to different ways of working would have a profound effect on their jobs and the nature of their work and the nature of the interaction with the citizen.

“So I think people shouldn't get too consumed with language, they should actually look at the substance and ask themselves: what are the real changes that are going to change their jobs, their relationship with the citizen, and the way that public service supports the agenda of the government and, and provide services to the citizens of this country.”

It is difficult, though, to not get consumed by the language. Barbs against the civil service have, sadly, been the marker. Sedwill’s time at cab sec started with him writing a letter to The Times to defend his one-time Home Office colleague and then-Brexit negotiator Olly Robbins from anonymous accusations of leading a “Rasputinesque” Remainer plot. Fast forward to today and so-called government sources have been quick to criticise what they seem to see as reluctance among officials to return to their offices after the coronavirus outbreak. 

In between, civil servants have faced an almost daily caricature of being anti-Brexit bureaucrats and out-of-touch pen pushers. Sedwill himself has become a much-criticised public figure, accused of trying to thwart Brexit, having a "rapacious appetite for power" and of using a leak investigation to forward a personal vendetta against a serving minister (see box). 

But at the Blavatnik last month, Sedwill said bad briefings don’t get under his skin. 

After all, he told the audience, “I’ve had a gun in my face from Saddam Hussein’s bodyguards; a bomb under my seat at a polo match in the foothills of the Himalayas; I’ve been hosted by a man plotting to have me assassinated; I’ve been shot at, mortared and even had someone come after me with a suicide vest. 

“I’ve had a gun in my face; a bomb under my seat; I’ve been hosted by a man plotting to have me assassinated; I’ve been shot at, mortared and had someone come after me with a suicide vest"

“So when people ask me how I handle the political sniping which is a regrettable feature of modern governance, I simply remind myself that it really isn’t as bad as the real thing.” 

Sedwill’s departure follows some high-profile exits by other perm secs – with  leadership changes at the Cabinet Office, BEIS, the Home Office and the Foreign Office. (The latter two, according to a particularly vicious briefing to the press, had been “on a No.10 hit list” for removal.) 

Home Office perm sec Sir Philip Rutnam’s public resignation in February was particularly explosive; Rutnam is now suing the Home Office for constructive dismissal, alleging home secretary Priti Patel had created a “culture of fear” and failed to distance herself from atttacks on him (accusations she denies). With the tribunal ongoing, Sedwill won’t comment on the Rutnam affair. 

Sedwill has said at committee hearings that while “never pleasant”, he had found bad briefing “goes with the territory”. That sounds like a far cry from that letter to The Times, which said MPs who criticise civil servants anonymously should be “ashamed of themselves”. 

Is he resigned to such hostility for his successors? No, he insists. “I think we should challenge the legitimacy of people who can't answer back being briefed against... it is unreasonable that people who, by convention, don't answer back and don't respond to every criticism, are subject to this kind of – usually anonymous – attack and snipe.” 

Sedwill says he will continue to defend civil servants in his remaining weeks as their boss – and remind politicians that such behaviour is “counterproductive”. Asked whether they stick up for officials enough, he says ministers have gone on the record and been “very supportive of the civil service”. 

“The prime minister himself has paid very warm tribute to individuals, including to me... [and] he's spoken of his appreciation for the amazing job the civil and the wider public service has done on Covid, and so on.” 


Just in shot on Sedwill's webcam during our interview is a rack of medals and the corner of a Union flag. He received the former in 2010 when he left Afghanistan, where he had been ambassador and then NATO’s senior civilian representative. The flag was flown at what he describes as “the most incredible leaving ceremony” – one of his fondest memories of his career. 

“The entire Afghan cabinet turned out for the farewell ceremony. It was an extraordinarily moving moment, after devoting two and a half years of my life to this country, and to the most intense experience I've ever had in public service and to have that recognition for it. And it was also very hard to leave.” 

As he prepares for another departure – albeit with rather less pomp and fanfare – Sedwill must be thinking about what will come next. How does it feel to be trading in a career spent running towards danger – literal and otherwise – for something different?  

“Well, I don't know yet, because I haven't tried the ‘something different’,” he says. “But you know, I've had a spectacular run. I've done over 30 years, I've enjoyed every job that I've done.” 

He has “perhaps a third of my career still ahead of me”, he adds. At the moment, he’s giving little away about what it might entail, beyond his new G7 role. 

An overseas role is “definitely an option” Sedwill says, adding that international public service would be “a very natural place” for him.  

“But I'm also just looking forward to trying some different things. I've never really done anything very significant in the private sector, apart from the jobs one does as a youngster. So I'd like to see if there's any way that I can bring some of my experience and skills to bear there.” 

CSW wonders how this most reluctant of cabinet secretaries thinks he will be remembered once he has left government – and how he would like to be remembered? 

“I hope I will be remembered as someone who... always marched to the sound of gunfire, always took up the challenge, always sought to do my duty, and always sought to make an impact in any job that I've done.” 

Sedwill on… Windrush 

Last month, home secretary Priti Patel announced plans for “sweeping” reforms to the Home Office in the wake of the Windrush scandal. Mandatory training on race, more inclusive policy developmenand more diverse job shortlists would help the department become "fair, humane, compassionate and outward-looking" after a review found it had demonstrated “institutional ignorance on race”. 

Now that the lessons learned review has been published, are there things Sedwill thinks he could have done in his five years as Home Office perm sec to minimise the harm to the Windrush generation?  

He says that, as he has told MPs before, he wasn’t aware it was happening. “Had I been made aware of it when I was at the Home Office – that problem which went back over many, many years, [and spanned] different governments – we would have sought to deal with it then.” 

He says the checks and balances of the immigration system – including inspections, parliamentary committees, public feedback, MPs’ letters and judicial scrutiny – all failed to identify the harm being done.  

“That is one of the lessons: that we couldn’t rely upon even the most elaborate sets of checks and balances to bring those problems to our attention. Had they done so, we would have tackled it, and they didn't, and I'm really sorry that they didn't.” 

“We couldn’t rely upon even the most elaborate checks and balances to bring those problems to our attention. I'm really sorry that they didn't” 

He says it’s also important to look at the “underlying structural issues” behind the scandal – and that the department “didn’t understand” at the time that people were getting caught out because they didn’t have the documents to prove their right to be in the UK. “Then, of course, that was compounded by enforcement action being taken against them.” 

There is a question about people on the front line feeling “empowered” to raise problems. “I think it's worth asking ourselves whether caseworkers at the sharp end realised there was something going wrong here, but didn't really feel they had the feedback loop to the centre of the department, to the policy level, to be able to identify those problems.” 

Does Sedwill think there was a problem with leadership structures or style at the department while he was there? “No. I mean, in my time as permanent secretary at the Home Office, we had a whole range of really difficult issues in the immigration system – many of them brought to us by people at the front line, some of them identified by the chief inspector of immigration, for example. But if you’d asked the chief inspector who was there during most of my time, he would say that he never identified anything that the caseworkers themselves hadn't essentially brought to his attention.” 

He adds: “I spent a lot of time out on the front line talking to caseworkers, trying to ensure that we had the right mechanisms in place. And, as I say, one of the questions is: we identified many, many problems in the immigration system and fixed them. Why didn't this one come to our attention?” 

Sedwill on... the Huawei investigation

As cabinet secretary, Sedwill has overseen many leak investigations. By far the most high profile was into unauthorised disclosures from National Security Council talks about the involvement of Chinese telecoms company Huawei in UK infrastructure. 

Then-defence secretary Gavin Williamson was sacked after the probe concluded there was “compelling evidence” he was responsible for the leak. 

Reflecting on the investigation, Sedwill says the fact it concerned information from the National Security Council – “a forum in which it's always been possible to have the most sensitive discussions about the most sensitive security issues, and be completely confident that nothing would come out” – made it unique. 

He has little to say about how felt to be responsible for overseeing the probe – other than to note it was a “particularly thorough and intrusive” investigation. But he is quick to head off the rumours that swirled at the time that Williamson’s sacking was retribution for bad blood between the two.  

“It was for the prime minister of the day to decide what action to take as a result. In the end, she was the arbiter of the ministerial code,” he says. “I make no recommendation on something of that kind. My job is simply to present the results of the investigation – which is conducted by professionals, not by me, under my aegis obviously – to the prime minister.” 

In the end, Williamson spent just two months outside cabinet before he was appointed by the new prime minister, Boris Johnson, as education secretary in July 2019. 

CSW wonders if that makes Sedwill question the value of the investigation or its findings. “Not at all. There were consequences decided by the last prime minister; this prime minister chose to appoint him to the cabinet. And he's doing a job as the secretary of state for education and he and I have a perfectly good relationship as a result.” 

Sedwill's CV highlights

  • 2018-2020 Cabinet secretary and head of the civil service
  • 2017-2020 National security adviser
  • 2013-2017 Permanent secretary, Home Office
  • 2012-2013 Political director, Foreign Office 
  • 2010-2011 NATO senior civilian representative in Afghanistan
  • 2009-2010 HM ambassador to Afghanistan
  • 2006-2008 Director, UKvisas
  • 2005-2006 Deputy director, Middle East and North Africa, Foreign Office
  • 2003-2005 Deputy high commissioner to Pakistan
  • 2000-2002 Private secretary, Foreign Office
  • 1997-1999 First secretary for political-military affairs and counterterrorism, Cyprus
  • 1996-1997 First secretary and UN weapons inspector, Iraq
  • 1991-1994 Second secretary, Egypt
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