The Prime Minister must make sure that our separation from the rest of our continent does not compromise the UK and the EU's crucial ability to combat external threats from terrorism, from Russian expansionism, from foreign government sponsored political subversion and from cyber aggression. Without doubt , the U.K.'s departure from the EU is likely to create potential additional divisions and weaknesses within our continent which may well be exploited by foreign powers, especially Russia and possibly also the USA and China.

Brexit-related promises (about UK and international security) from Boris Johnson and his colleagues:

Vote Leave's 2016 campaign manifesto (drawn up by that organisation's campaign committee, of which Boris Johnson was a prominent member) sought to convince the public that "European cooperation will continue in fields where it already exists" such as "counter-terrorism". Our Prime Minister will need to be extremely proactive to ensure that our continent is not made more vulnerable as a direct and indirect result of Brexit.