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Would a New SDSR Be Needed After a Brexit Vote?

Malcolm Chalmers
Briefing Papers, 3 June 2016
UK Defence Policy, Defence Spending, European Union, Brexit, Scottish Defence and Security Policy, UK, Defence Policy, UK Defence, Europe
Professor Malcolm Chalmers presents a personal argument stating that a UK decision to leave the EU would be as significant a shift in UK national strategy as the decision in the late 1960s to withdraw from bases East of Suez and, as a result, would necessitate a new Strategic Defence and Security Review (SDSR).

In November 2015 the UK government published its latest SDSR, setting out its national security strategy and announcing key decisions on strategic and spending priorities. Because of the political sensitivity of the subject, and the prime minister’s then-ongoing negotiations on EU reforms, it did not assess the defence and security implications of a UK exit from the EU.

Most of the leading participants in the referendum debate – from both sides – accept that an exit would lead to a fundamental change in the nature of the UK’s future relations with its European neighbours. As a result, if the UK votes to leave the EU there would be a very strong case to conduct a fresh review of the SDSR’s key strategic judgements and policy choices, which would likely begin by the end of 2016, with completion by the spring or summer of 2017.

In a 2017 SDSR current plans for defence spending over the next decade might have to be revisited, especially if projected GDP growth fails to materialise in the aftermath of an exit vote. While a Brexit could lead to calls for the UK to return to a more global defence posture, there could simultaneously be countervailing pressures on the UK to redouble its commitment to European defence, in part to address concerns that an exit from the EU would risk undermining confidence in NATO, and in part because the UK’s commitment to European defence would represent one of its few bargaining chips as it entered a period of tough negotiations on the terms of its future economic engagement with its EU neighbours.

At the same time, Brexit would not necessarily increase the likelihood that Scotland would then vote to leave the UK. Indeed, a British exit from the EU would probably make it significantly harder for Scotland itself to then become an independent member of the EU. But the possibility of Scottish independence, in some form, would remain an ongoing risk to the stability of the UK’s defence arrangements.


Malcolm Chalmers
Deputy Director-General

Professor Malcolm Chalmers is Deputy Director-General of RUSI and directs its growing portfolio of research into contemporary... read more

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