Cameron makes appeal to 'uncertain' referendum voters

The Prime Minister admitted the referendum would produce some “strange bedfellows” as he campaigns on the same side as Labour leader Jeremy Corbyn and conceded he was disappointed at London mayor Boris Johnson’s decision to back a ‘leave’ vote.

Mr Cameron also suggested that before entering Downing Street he might have found himself arguing for a British exit from the EU.

Speaking at the offices of telcoms firm O2, one of 36 leading companies to sign a letter supporting EU membership today, The Prime Minister said he had considered the matter “very very deeply”.

“I think six, 10, 15 years ago I don’t think I believed that Europe was as important to our security as I believe it is today because I’ve seen with my own eyes just how important the security, the intelligence, the sharing of information is.

“I’m not sure six, maybe 10 years ago, I thought that Europe was quite so important for Britain getting things done in the world.

“I thought obviously NATO matters, our partnership with America matters but I see and I’ve seen this for six years that if we want to fix stuff whether it is trying to stop people smugglers in the Mediterranean, whether it’s trying to stop pirates off the coast of Africa, whether it’s confronting Iran about the nuclear programme, whether it’s trying to get better results in Syria we gain by sitting round that table with the French, with the Germans, with the Italians and getting things done.”

In the Commons on Monday, Mr Cameron had appeared to take a swipe at Mr Johnson suggesting that the London mayor was using the referendum to further his Conservative Party leadership ambitions.

But today he sounded a more conciliatory tone.

Mr Cameron described Mr Johnson as a “great politician” and a “great friend” with “a lot to give” to the Conservative Party and the country.

“But on this issue I think he’s got it wrong, I think he’s reached the wrong conclusion. So we’re going to have, I hope, a reasonable and civilised argument both between us and between other parties,” he said.

The Prime Minister confirmed he had been talking with Mr Johnson “for many weeks” over the issue and was “disappointed” at his decision.

“I would say to anyone who is taking time to decide, who is thinking about it, weighing it up and trying to work out what’s best, that if you’re not certain surely the best thing to do is to back the side that has the security and safety of what we know.”

He added: “There is uncertainy, there is risk, there is a leap in the dark if you leave the single market, leave the EU, so if you’re not certain don’t leap.”