David Cameron just said ISIS would be 'happy' if Britain left the EU

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Prime Minister David Cameron spoke in central London on Tuesday about the impacts of a Brexit.

David Cameron spoke to an audience of business leaders on Tuesday about how Britain's security would be affected by a Brexit.

In his speech, he claimed the leader of IS would be "happy" with if Britain left the EU and that a Brexit would seriously undermine national security.

Speaking at Mansion House in central London, the prime minister was asked how national security would be impacted if Britain voted to leave the EU on June 23.

He said: "Who would be happy if we left? Putin would be happy, I suspect Al Baghdadi would be happy."

Abu Bakr al-Baghdadi is the leader of the terrorist organisation ISIS (also known as ISIL, Daesh and the Islamic State).

He added: "You keep yourself safe not simply by having a border but by working with other countries ... I'm not saying it's the only thing that keeps us safe but it helps.

"I would say to people, who do you believe about keeping us safe? The former head of MI5, the former head of MI6 or the people in the Leave campaign who do not have direct experience?"

Cameron was referring to former MI5 head Eliza Manningham-Buller, who last week said leaving the 28-nation bloc would mean withdrawing from a major information-sharing forum and consequently would present "real risks" to Britain's security.

However, Manningham-Buller's and Cameron's remarks put them at odds with former MI6 chief Sir Richard Dearlove.

In March, Dearlove said that as well as giving the country greater control of its borders, leaving the EU would mean Britain could deport extremists with greater ease as it would no longer have to comply with Human Rights regulations.

The issue of Britain's security has been a major talking point in discussions about how the country should vote on June 23, with senior security figures lining up on either side of the debate.