He said: “I welcome the agreement we've reached with Turkey today. We will work together to stop migrants leaving Turkey in the first place to stop at sea those that do leave and turn back the boats and return back to Turkey those that do make it to Greece."

“For the first time in this crisis I believe we have a plan if properly and fully implemented that really could help to make a difference - deterring people from coming and shutting down the trade that smuggling gangs have been exploiting.”

He added: “It will require a comprehensive and large-scale operation. Britain will help. We have the expertise we have skilled officials.”

Cameron also confirmed Britain would not be bound by the visa-free agreement for Turkish nationals.