Mark Sedwill’s three hats: the pros and cons of no longer having a full-time national security adviser

Re-combining the role of national security adviser with the post of cabinet secretary undoes a reform made in 2010. Dr Joe Devanny asks if the decision is the right one.

Photo: Louise Haywood-Schiefer

By Dr Joe Devanny

01 May 2019

In late October 2018, when Sir Mark Sedwill was confirmed as the late Lord Heywood’s permanent successor, he inherited two portfolios: cabinet secretary and head of the home civil service. In addition, Sedwill decided to combine these responsibilities with those of his previous post of national security adviser. At first it wasn’t clear whether this “triple hatted” arrangement was only temporary, but it has recently been confirmed that no further change is expected during Sedwill’s tenure as cabinet secretary – or, at least, during that part of Sedwill’s tenure that is coextensive with Theresa May’s premiership.

As Sedwill himself has explained, he is far from being the first cabinet secretary to assume the role of advising the prime minister and cabinet on matters of security. The origins of the cabinet secretary and secretariat are to be found in efforts to improve the management of government business during the first world war, and subsequent cabinet secretaries played important Whitehall roles in most of the major conflicts that the UK participated in throughout the twentieth century. In fact, the process of paring back the security and intelligence elements of the cabinet secretary’s portfolio occurred relatively recently, culminating in David Cameron’s May 2010 reforms that created the National Security Council and the post of national security adviser.


Prior to Cameron’s NSC reform there had been a gradual expansion of Cabinet Office advisory and secretariat capacity to deal with foreign policy, intelligence and security issues, including the creation shortly after the 11 September 2001 terrorist attacks of a permanent secretary role coordinating security and intelligence, alongside other similarly senior officials advising the prime minister on wider international and specifically European affairs. Whilst European issues continued to be treated separately even after the 2010 reforms, the other foreign and security policy responsibilities were then rolled up in the national security secretariat under the aegis of the national security adviser. 

There are three points that flow from this recent history and which have a direct bearing on how we should interpret Sedwill’s decision to re-combine national security with the cabinet secretary’s other responsibilities.

First, Sedwill’s background is stronger in security and foreign affairs than was the case for many of his recent predecessors as cabinet secretary. It makes sense, therefore, that he feels more confident retaining this portfolio than he might have done had he spent most of his career in, for example, the Treasury. An analogy might be made with Sir Kim Darroch, whose strong European background might have led him to combine national security with European responsibilities during his tenure as national security adviser. Interestingly, however, Darroch did not do so, and the separate senior post of prime minister’s Europe adviser remained during his tenure in the Cabinet Office and continues today.

Second, the evolving nature of senior official advisory roles in the Cabinet Office and Downing Street owes much to the preferences and requirements of the incumbent prime minister. Margaret Thatcher, for example, felt the need to add a senior foreign affairs adviser in Downing Street in order to supplement advice she was receiving from the Foreign Office. Her successor, John Major, initially continued this practice, but then allowed this post to lapse and instead added a more junior foreign affairs post to his private office. There is no immutably, uniformly applicable model for configuring these responsibilities at the centre of government: the processes and personalities need to work for the prime minister of the day, and in light of the major contemporary challenges facing government. In this sense, Sedwill has described the main motivation for his role as “to make a success of Brexit”.

And third, irrespective of the configuration of senior posts, the longer term trend has been the steady growth of the foreign and security capacity in the Cabinet Office, over the last 30 years and especially since 2001. It is generally accepted that, as prime ministers have become more directly and regularly involved in the management of foreign and security policies – and as these two areas have become more inextricably connected, for example in the cases of terrorism or the cyber threat, transcending the divide between domestic and foreign policies – it is simply inadequate to preserve the traditionally very small national security function at the centre. Whilst Sedwill has introduced a new framing concept, the “fusion doctrine”, into government, it has long been apparent that there is a need for “fusion”, “joined up” approaches and more rigorous, coordinated implementation of policies by a range of different departments under the umbrella of national security.

Of course, in one sense it is difficult not to interpret Sedwill’s “fusion doctrine” and his decision to re-combine national security in the cabinet secretary portfolio as an indication that he feels previous incumbents were pursuing an insufficiently “fused” approach to policy. Perhaps he also feels uniquely able to devote the requisite focus, nervous energy and bandwidth to all his re-configured, triple-hatted responsibilities, without loss, as compared with the status quo ante in which two top officials took ultimate responsibility for the same corpus of issues.

“In one sense it’s difficult not to interpret Sedwill’s ‘fusion doctrine’ and his decision to re-combine the roles as an indication that he feels previous incumbents pursued an insufficiently ‘fused’ approach”

In another sense, however, this critique of implicit hubris is misplaced, as Sedwill could re-configure his team, increase its size and appoint a larger number of senior deputies across the various portfolios to share his load. But some will see even this as nevertheless involving an indelible degree of loss: where previously the 2010 reform had created one top official with responsibility for and bandwidth to address the full spectrum of national security affairs, there is now only part of Sedwill’s time, plus the segmented efforts of his two deputies – the same number of national security deputies, in fact, that he relied on when still the full-time national security adviser. It is a smaller number of deputies than some of his predecessors in that role possessed. If there was value, prior to Sedwill’s appointment as cabinet secretary, in having a full-time national security adviser with the right of direct access to – and the ability in practice to get the regular attention of – the prime minister, it is slightly difficult to see why there would not still be value in continuing with such an appointment now.

Clearly, it would not be an upgrade on the present to have a hypothetical full-time national security adviser who was less able than Sedwill, less qualified and less likely to secure the necessary prime ministerial access and attention to national security issues. But there is no reason, in principle at least, to believe that such a person would have been appointed had the decision been made to recruit a successor.

Deciding to reduce the number of permanent secretary level officials in the Cabinet Office by ending the post-2010 consensus that there should be a full-time national security adviser might increase the likelihood of a successful Brexit and a well-executed fusion doctrine. But, then again, it might not. An independent review of the national security apparatus might contribute some useful challenge to – and alternative perspectives on – this decision, but the prime minister and her cabinet secretary are undoubtedly busy and appear as yet not to see the need for it. It will be interesting to see, however, whether the UK’s next prime minister favours this new normal or returns to the old one.

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