Verdict: Miliband picked apart the holes in Cameron’s EU policy

Finally, we have a clear impression of Ed Miliband's EU strategy. It's been a confusing road. A noticeably eursosceptic speech and a few off-the-cuff comments towards the end of last year suggested he was moving towards backing a referendum, but since the weekend he and shadow foreign secretary Douglas Alexander (who always privately argued against giving the public a direct say) have been clear they will oppose it. Today we saw why.

Common sense has it that no-one profits in British politics from supporting the EU, but today Miliband used his position to push David Cameron further away from the centre, closer to the extreme eurosceptic wing of his party. In the process, he made the prime minister look weak in the face of his backbenchers, making concessions to radicals who will never be satisfied until they're out.

Miliband did it rather effortlessly, with a deft, witty performance which began by recalling Cameron's regret over his party spending so many years "banging on" about Europe. "Is he glad those days are over?" the Labour leader asked sarcastically.

Cameron tried to adopt a statesmanlike tone, warning of "massive changes" taking place on the continent. "I know where I stand," he insisted, a little unconvincingly.

"Let's hope we find out where he does stand today," Miliband replied. "I suppose I should congratulate him on one thing – for having decided the date of his speech. Another example of the Rolls Royce operation in Downing Street."

Cameron tried to counter with a snide remark about Miliband backing Balls for the shadow chancellor role into 2015, but it wasn't his day. With a devious twinkle in his eye, Miliband reminded Cameron of when they stood "shoulder to shoulder, two parties in the national interest" and walked into the voting lobby to shoot down Tory attempts to wreak havoc in the EU. It was effective stuff, the leader of the opposition needling his way into the PM's vulnerable spot, as if picking apart holes in an old jumper. The Tory benches looked extremely glum, although one or two MPs smiled wearily.

"Why doesn't he get on with substance and give up the feeble jokes?" Cameron demanded.

"I thought the jokes were pretty good," Miliband replied, evidently enjoying himself, increasingly confident in putting the script to one side and speaking off-the-cuff. Before long he was quoting Michael Heseltine and getting Tories to boo their own man.

Nick Clegg looked laden with weighty frustrations, inwardly bemoaning how avoidable it all was, barely concealing his need to scream 'I told you so' at his coalition partner.

Miliband was finally making use of the ammunition available to him, finally hitting a ball into an open goal. His central argument – if a referendum would be destabilising now, why would it be any different in five years? – has few effective answers.

"He thinks his problems end on Friday [when he makes the EU speech]," Miliband told the Commons. "They are just beginning." It was the truest thing the Labour leader had said in PMQs for a long time.

Cameron frantically evaded a question on whether he had suspended Cabinet's collective responsibility on the issue, allowing Miliband a final dig and flourish. Once the leader of the opposition sat down, Cameron could barely make himself heard above the Labour cheers for 'more'. It flustered him and he ended up claiming, angrily and wrongly, that Labour supported the single currency.

Miliband probably went too far in suggesting the Tory party was in chaos over Europe – after all, it now has so few Ken Clarke-style europhiles left it is relatively united. But he managed to highlight the fraught relationship between leadership and backbencher. It is an argument which makes the prime minister look weak – so expect to hear it many times before the general election.