'We would have to start again with a blank sheet of paper as to how we build up that cooperation with our European partners'

Sir John Sawers says it would be hugely damaging if UK-EU relations collapsed to such an extent.

'It is not surprising that the people who have devoted themselves to serving the interests of this country are concerned about the direction in which the country is going'. / In an outspoken intervention, Sir John Sawers said it was "unwise" to hold a referendum in the first place and warned that political turmoil had damaged the UK's standing on the world stage.

The former head of MI6 says any Brexit makes security difficult to manage but "the harder the Brexit, the greater the damage". / The blunt warning comes from three men who have served at the very top of the British defence and security ...