Last month the Prime Minister vetoed a new European treaty for greater fiscal intergration between eurozone countries saying there were not enough safeguards for the City.
Yesterday the treaty was signed without Britain.
Mr Miliband said: “I’m very concerned about what David Cameron has done. He trumpeted last December that he had got a great deal for Britain and protected us.
“And the way Europe was going to go about thisTreaty wasn’t going to affect Britain. Now he has sold us down the river on a lot of things.
“I am going to ask him what exactly has he agreed, what protections has he got for Britain. I take the simple view: he would have been better off staying at the table and negotiating for Britain rather than pretend he had made progress but failing to do so.”