As the cabinet secretary stands down after more than 30 years in the civil service, CSW asks people who have worked with him: who is Sir Mark Sedwill?


The legacy someone wants to leave behind can tell you a lot about them. Sir Mark Sedwill has said that after more than three decades in public service, he wanted to 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”. And as he steps down as cabinet secretary and head of the civil service this week, CSW asks: will he? 

Former ministers paint Sedwill as a congenial and capable civil servant who has been utterly dedicated to each of his jobs, no matter how challenging. And whether deputy ambassador in Pakistan just after 9/11, running the Home Office, or leading the government through two simultaneous national crises, they have definitely been challenging. 

There is no doubt in anyone’s mind that he has, in his own words, sought to do his duty. Ex-officials say he was kind and made time for them in ways they might not have expected from someone of his rank; although those who crossed paths with him in his last years in government suggest that he had less time for, or perhaps less interest in, the nitty-gritty of civil service leadership and reform than his predecessors. 


Sedwill’s Whitehall career began in the Foreign Office in 1989 in the Security Coordination Department and the Gulf War Emergency Unit. Postings in Egypt, Cyprus and Iraq followed, including a stint as a UN weapons inspector, before he returned to the UK in 2000 to become private secretary to foreign secretaries Robin Cook and Jack Straw. 

Denis MacShane, a Europe minister in the New Labour government, says Sedwill fit the mould of Foreign Office private secretaries: “the crème de la crème of the young high flyers, the future ambassadors… they work 12, 14 hours a day, they're very dedicated”. 

“In the Foreign Office, I met some of the smartest and some of the dumbest people in Britain. Mark was in the very bright category”

“In the Foreign Office, I met some of the smartest and some of the dumbest people in Britain and you could never quite tell when you began the conversation or the meeting. But Mark was certainly in the very bright category,” he adds. 

MacShane says Sedwill supported Cook through “one of the more creative periods of Foreign Office activity and British foreign policy”. Cook was, he adds, “a very dynamic foreign secretary, to put it mildly”, fighting to set up the International Criminal Court; reorientating British foreign policy to be more engaged in Europe; and dealing with the fallout from the toppling of Indonesian dictator Suharto. 

When Sedwill moved overseas again, MacShane notes he was “promoted fast and hard because he was highly trusted and very good, having worked in some extremely difficult and problematic parts of the world”. In 2002, he was promoted to deputy high commissioner in Pakistan, and he would later serve as ambassador, then NATO senior representative, in Afghanistan. 

David Walker, who worked with Sedwill in Pakistan, says it was a trying time to be based there. “It was a difficult situation in Islamabad for us in the high commission because it was post-9/11, so there were a number of evacuations in that period... Mark handled it professionally and well and was universally liked and respected.” 

“It was a difficult situation in Islamabad post-9/11. There were a number of evacuations... Mark handled it professionally and was universally respected”

Walker, who was estates manager for the high commission, used to walk Sedwill’s dogs around the compound with the then-deputy ambassador – who he calls a “regular guy and a decent bloke” – and “chew the fat”. He recalls: “We were all stuck there because times were difficult and we couldn’t go out and about as much as we used to in the previous years. When you’re living in a goldfish bowl like a British high commission compound, you’re all thrown together and you get to know each other a lot better. 

“We had a laugh and a drink. One of his major tasks – although we were all responsible for it – was to try and be upbeat and try to keep our chins up and try to get through each day safe and sound. And morale was very good.” 

Walker’s assessment of Sedwill is a common one: friendly, professional, down to earth. Former Cabinet Office minister David Lidington says the outgoing cabinet secretary was good humoured and “never pompous”. More than one interviewee describes Sedwill as “witty”; onetime immigration minister and fellow cyclist Robert Goodwill says the two used to joke about abolishing the government car service and issuing ministers with Brompton bikes instead. 

Meanwhile in interviews, public events and select committees, Sedwill has shown he has the art of using many words to give very little away down to a fine art. 

There are those who attribute this personable, if sometimes guarded, demeanour partly to the less-public facing years of Sedwill’s career history. A former colleague who remembers him as a promising young private secretary notes he had not taken a “conventional” diplomatic career path to get there – but that his background required excellent people skills. 

Another says that Sedwill “has had one career after another”. They note that he is now president of the ultra-discreet Special Forces Club, whose members include SAS members and spies, adding: “That should tell you something”. 

Asked in 2018 if he would admit to having been a spy, Sedwill told CSW: “No-one is ever going to answer that question. Apart from probably the chief of the Secret Intelligence Service.”  


Whatever the nature of his overseas postings, Sedwill’s experience in turbulent environments clearly gave him practice in staying calm under pressure. Lidington says the “completely unflappable” then-national security adviser’s role in dealing with the 2018 Novichok attacks “should not be underestimated”. 

And as Sedwill said this summer, “I’ve had a gun in my face from Saddam Hussein’s bodyguards; a bomb under my seat at a polo match... I’ve been hosted by a man plotting to have me assassinated.” He said the anonymous sniping against him that became a staple of his time at the top of the civil service wasn’t “as bad as the real thing”. 

Sedwill’s security experience also shaped his time at the Home Office. Patrick Stevens, who was international director at the Crown Prosecution Service at the time, says Sedwill’s appointment as permanent secretary in 2013 marked a “sea change in leadership and direction” of what he calls a “One HMG approach to international justice threats”. 

“A lot of people in government in that international justice, rule of law space were doing a lot of work to try and become more joined up – and one of the huge impetuses for that was Mark being made perm sec. 

“His leadership went way beyond the traditional boundaries within Whitehall. He lived and breathed that joined-up government, that strategic vision”

“I very much felt his leadership went way beyond the traditional boundaries within Whitehall. He lived and breathed that joined-up government, that strategic vision,” he adds. It was the first time Stevens had felt there was a “very clear vision that the Home Office recognised that the protection of the public didn't stop at Dover; it started upstream”. 

Stevens says he saw the same “sharpening of focus and of purpose” when Sedwill became national security adviser in 2017. “Even from a non-policymaking department like the Crown Prosecution Service, I saw a clear step... a clarity of comms, purpose and leadership is something he brought to the table all the time.” 

At that time, Alex Thomas was running the private office of Sedwill’s predecessor as cabinet secretary, Jeremy Heywood. Now a programme director at the Institute for Government, he says Sedwill “was and is an impressive operator”. 

When Heywood took a leave of absence to undergo cancer treatment, Sedwill was “really the only choice” to step in as acting cab sec, Thomas says. “That was because of the skills he had in getting things done, the authority he had and the confidence that the prime minister had in him.” 

But he says it appears there were elements of being civil service boss that took up more of Sedwill’s attention than others. “Civil service policy questions, I suspect, excited him less than some others. His experience was in foreign policy, security policy, home affairs, and I think his leadership style was to focus less on the technical side and more on the human and charismatic side.” 

“Civil service policy questions, I suspect, excited him less than some others”

And Thomas says Sedwill probably spent less time on managing the civil service, which he attributes partly to the “all-consuming nature of Brexit”. That was just one way his leadership style differed from that of Heywood, a policy specialist who was known as a “mandarin’s mandarin”. 

“Jeremy had developed a leadership style that was quiet and reflective; Mark was more extroverted and assertive. He was someone who had a strong personality, who was assertive, confident in speaking to very large groups of people, and he was also confident sticking his neck out,” Thomas says. He recalls the letter Sedwill wrote to The Times as acting cab sec calling for an end to “sniping” against civil servants. Chastising MPs – who were responsible for much of that sniping – so publicly was unprecedented. 

Thomas remembers Sedwill, the securocrat who had bombs planted under his seat, having a reputation as an “action man”. But, he says, “that caricature belied quite a subtle and sophisticated people person. I saw him be quite acute about people.” 

Stevens says he felt that acuity first hand; while at the CPS he found Sedwill “incredibly encouraging and complimentary – and supportive of me personally and what we were trying to do in a way that went way beyond his remit. He made me feel as if I was part of a joined-up thing, and that we mattered.”

A former colleague, who also describes Sedwill as “very kind and personally supportive”, says breaking down barriers between departments has been a “strong feature of his leadership” over the last two years too. “Something Mark said early on which I think he genuinely believed is that he’d never met a civil servant that didn’t want to be collaborative.”

Sedwill has certainly beaten the drum for 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. 

There was no doubt Sedwill gave the role his all, they add – stressing how difficult it must have been to succeed Heywood in such tragic circumstances. Sedwill himself has described Heywood as “unfollowable”. 

Then there was the political environment he had to contend with: a general election, a new prime minister, Brexit, a pandemic. “Throughout all of that, his integrity has never been in doubt,” the former colleague says.

“The cabinet secretary job is huge. You have to do what you’re good at.” Heywood’s command of economic and domestic policy was “superb”; Sedwill was an expert in security and foreign affairs. “As national security adviser I think he was utterly brilliant and it’s a great loss. They were bringing different strengths to the role.” 

It is, they acknowledge, fair to say Sedwill was less interested in civil service management. Other former colleagues also say topics like civil service reform, diversity and moving officials outside London did not appear to hold the cab sec’s attention the same way matters of national security did. 

And they say retaining three jobs – Sedwill was cabinet secretary, NSA and head of the civil service – was unwise. “He should have appointed a deputy on the economic and domestic side.” 

"It was good in theory, and he definitely meant it as a strategic approach to government. He just had no idea or interest in ‘how’. It just didn’t arise"

A former permanent secretary colleague of Sedwill’s agrees that had the then-cabinet secretary appointed a de facto deputy cab sec he could lean on – a “details person” – his approach would have been more effective. “He didn't make as much use of people as he might have.”

One critical example was the Fusion Doctrine – which they say was a “very big deal” for Sedwill. Having implemented the approach in the national security space, the cab sec spoke often about wanting to use it to break down silos elsewhere in public service. “It was good in theory, and he definitely meant it as a strategic approach to government that he really did buy and he really did care about.

“[But] he just had no idea or interest in ‘how’. It just didn’t arise. That was his thing: that he would set the big picture, ‘Here’s the vision – come on, get on with it.’ And he was great at standing up in front of an audience and setting direction.”

And while Sedwill may have had success in getting different agencies to collaborate when he was at the Home Office, the ex-perm sec says he was “hopeless” at getting the top team to work together across their departmental boundaries.

“He's a tough guy in charge. And no doubt in the early stages of his career, being tough and secretive is absolutely vital. But that's a very different skillset than is required if you want to get a group of people who work for different sectors of secretaries of state to collaborate. That requires people to share and be open and trusting – and the civil service is not particularly good at that anyway.”

Another former official who worked with Sedwill when he was cabinet secretary notes his background meant he was “professionally conditioned, and to some extent personally inclined, to work closely with a very small number of people”. 

“Securocrats work in extreme situations and have to depend on each other in ways the rest of Whitehall doesn't have to. That puts a bit of distance between them and everybody else”

“I think there is a thing about securocrats – that because they work in extreme situations and they have to depend on each other in ways that the rest of Whitehall doesn't really have to mess with, they have very strong bonds among themselves and that puts a bit of distance between them and everybody else.” 

Sedwill’s fellow perm secs felt that distance sometimes, this ex-official says; as did his private office, which oversaw his schedule and meetings, which risked some conversations being overlooked. “I think that can only have been massively exacerbated by the three hats he was wearing. His time was under huge pressure.” 

There was also a question of priorities, however. This same ex-civil servant notes that Sedwill did not attend last year’s Civil Service Awards – a chance for the head of the civil service to show appreciation for their staff – dedicating that time to the responsibilities of his NSA role instead. That was seen as a misstep. “In his internal priorities, they weren't high enough.” 

But they add: “He's a really nice bloke. When you sit down with him, he is engaged and focused on people... and I'm absolutely sure he wanted to do the best for the civil service.” 

For one thing, Sedwill “fought the good fight on behalf of the constitutional principles of the civil service”. The cab sec endured several run-ins with Dominic Cummings and continued speaking truth to power, “but he was trying to do it in a phenomenally difficult environment”. So when the current administration’s regard for the constitution has been called into question – for example, during the PM’s controversial prorogation of parliament last year – “that genuinely wasn't for lack of trying on Mark's part.” 

Dave Penman, general secretary of the FDA union for senior civil servants, says Sedwill’s stint as cab sec “required a different kind of focus” to his predecessors’. 

"Look at what that must have been like supporting May with her own party against her, the turmoil, the constant attacks from within the party of government"

“Look at what that must have been like supporting May with her own party against her, with the turmoil that was going on, the constant attacks from within the party of government.” Adding to that Brexit, Covid and the government’s bending of the law and constitution, Penman says “few would envy his time in the role”. 

“And Gavin Williamson’s sacking… that’s leadership, that’s toughness, that’s resilience.” Sedwill oversaw the investigation that concluded Williamson was responsible for a National Security Council leak about the Chinese telecoms company Huawei’s role in critical UK infrastructure – though he told CSW it was the PM’s decision to sack the then-defence secretary as a result. 

“I’ve always found him approachable, robust but appreciative of the work of the FDA, particularly in standing up for the civil service values of integrity, impartiality and professionalism.” 


Sedwill’s unwillingness to be a “yes man” meant he faced many critics. But former ministers speak highly of him: Lidington says he found Sedwill “easy to work with”; Goodwill that he was “very switched on”. 

And Jonathan Powell – an ex-diplomat and Tony Blair’s former chief of staff – says he was impressed by Sedwill’s “positive, can-do attitude”. 

The first worked together directly after Powell had left government and was running Inter Mediate, a charity that works on reducing violent conflict by promoting dialogue between governments and insurgent groups. By then, Sedwill was in Afghanistan. 

Powell, who had played a critical role in the peace talks that led to the Good Friday Agreement, says Sedwill understood why there was a place for engaging with terrorist groups to find peaceful solutions to conflicts. “I found that refreshing, because not all mandarins get the need to do that.” 

“Lots of civil servants can be quite negative. He was always ready to try and find a way of doing stuff”

“Lots of civil servants... can be quite negative, can see all the reasons why you shouldn’t do something. It’s important that civil servants do say that, especially to ministers and people like me when I was a political appointee. 

“[But] he was always ready to try and find a way of doing stuff… Instead of seeing a problem as a problem he would see potential solutions. That’s what’s refreshing and why, almost certainly, Theresa May saw him as so useful.” 

Sedwill has said he never aspired to be cabinet secretary. But he had become May’s ally when she was home secretary and as he told CSW this summer, when Heywood became ill, he was “unable to persuade her” not to ask him to do the job. 

Lidington, who spent two years in May’s cabinet, says part of the reason the former PM “completely trusted [Sedwill’s] discretion” was his “willingness to be completely frank with her in private”.  

He adds: “Where he got frustrated was when he felt that ministers, either individually or collectively, were not willing to come to a decision. But he would work very hard to try and find a way through to devise a compromise that would work and move things forward. 

“And he also did work hard to try to make sure that the government machine was doing what needed to be done on no-deal planning.” He is convinced there is no truth to accusations in the press that Sedwill wanted Brexit to fail. 

Former immigration minister Mark Harper is equally confident Sedwill “would have been trying to deliver the government's objectives” on Brexit. While there were “political mistakes” with the withdrawal agreement, he says “the machine was doing what it was asked to do by its political masters”. 

“Where he got frustrated was when he felt that ministers were not willing to come to a decision. But he would try to devise a compromise”

When the two worked together, Harper says the then-Home Office perm sec did everything by the book: “providing rigorous advice, presenting you with options, giving you the pros and cons of different options”. 

“He very much recognised that advisers advise, they don’t decide, and once decisions were made, he was very good at executing… And that was the way he coached other civil servants to behave.” 

But the conversation that stands out most to the Conservative MP happened when he asked Sedwill to sit down with a young constituent who wanted to work for the Foreign Office, and tell him about the department. 

“Because I was a minister and I asked him, [Sedwill] probably did have to see him,” Harper says. But rather than the 10 minutes he expected, Sedwill spoke to the young hopeful for half an hour. “Half an hour of a permanent secretary’s time for somebody who’s 18, that’s quite generous.” 

And he also says he was struck by Sedwill’s counsel. “I’m paraphrasing, but he basically said: the best advice I can give you for being successful – in the civil service more generally, but specifically the Foreign Office – was go to university, go and get some life experience, get some rough edges and some bumps and scrapes and things. Then come to the Foreign Office and then the Foreign Office will smooth it all down again. 

“I thought that was not what you normally get told by people giving you career advice, you normally get ‘don’t do anything too exciting’ and all that kind of stuff. And I just thought that was actually quite good advice.” It is certainly advice Sedwill seemed to live by. 

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