By Steven Swinford, Deputy Political Editor

Daily Telegraph – 9 May 2016

David Cameron has been accused of "manipulating" the former head of MI5 into warning that Britain's national security would be put at risk by a Brexit. Lord Evans, a former director of MI5 and Sir John Sawers, a former head of MI6, said in a joint article that a Brexit would hamper

"our ability to protect ourselves from terrorists".

However, Julian Lewis, the Conservative head of the Defence Select Committee, said that Lord Evans had told him privately that leaving the EU would

"make no difference"

to national security. Speaking in a personal capacity he said:

"I had a conversation very recently with one of the two and I was quite impressed by the fact that although he told me he was in favour of remaining in the EU, it would make no difference to our security.

"I am very surprised and rather disappointed to see this article has appeared. I find it rather difficult to believe he has changed his mind in such a short period of time. I can only wonder if there's some sort of manipulation going on here."

However Lord Evans and Sir John denied that their intervention had been co-ordinated by Downing Street.

"We're not doing it at anybody's behest,"

they wrote in the Sunday Times.

"We are completely politically neutral."

They said in their article:

"Intelligence work today relies on the lawful and accountable use of large data sets to reveal the associations and activities of terrorists and cyber-attackers. The terms on which we exchange data with other European countries are set by agreement within the EU.

"As an EU member, we shape the debate, we push for what we think is the right balance between security and privacy and we benefit from the data that flows as a result."

Mr Cameron said that their article held an "important message".