A letter orchestrated by 10 Downing Street in February 2016 was signed by a number of senior and former members of the armed forces: however, this manoeuvre spectacularly backfired after it turned out that one of the claimed signatories had not signed at all. General Sir Michael Rose had not only not given his permission to be included, but had instead said that "sovereignty and security are intrinsically linked and in the recent years we've seen the EU erode our sovereignty". No. 10 was forced to issue a humiliating apology to Sir Michael.

Other respected military figures have come out in favour of leaving the EU, including Colonel Richard Kemp, former Army Commander in Afghanistan, who wrote an article in the Sunday Express of 28th February 2016 stating that "NATO is our main military alliance, not the EU. By leaving the EU we will gain far greater control of our borders and better confront these challenges that have the potential to undermine the very fabric of our society."

(See also these comments on security)