Cameron defends EU veto amid accusations of isolating Britain

The cornerstone of Cameron's defence of his veto was that neither the French nor the German leaders accepted his demands for "modest, reasonable and relevant" safeguards regarding financial services.

He said that by opposing EU treaty change at 27 and forcing an inter-governmental treaty "outside the EU", any further regulation agreed among the 26 will not affect the City of London, Europe's financial powerhouse. "A treaty outside the EU cannot do anything that cuts across existing EU legislation," Cameron argued.

This, however, was contested not only by opposition MPs, but also by EU economics commissioner Olli Rehn who earlier that day warned London that it will not escape regulation by staying outside the fiscal treaty agreed at 26 after the British decision to stay out of it.

Labour leader Ed Miliband agreed that "existing EU institution will be used. It would be clearly ludicrous for the 26 member states to completely re-invent a whole canopy of institutions." He challenged Cameron to point out where the threat to financial services was.

"Far from protecting our interests, he has left us without a voice. How can you call it a veto when the others are going ahead without you? That's called losing," he said.

Pressed by his own backbenchers not to concede any further powers to Brussels or else face a referendum in Britain, Cameron had put party interests above the national interest of being part of the negotiations on a new treaty, Miliband said, noting that other countries are also reluctant to give away new powers but remain at the negotiating table.

Miliband also pointed to the absence in the debate of vice-premier and Liberal Democrat politician Nick Clegg, who on Sunday had expressed his "bitter disappointment" over the outcome of the summit.

Grilled by several MPs to talk about the rift in the coalition and reveal why Clegg had not shown up for the debate, Cameron only said that the coalition parties cannot always agree on everything. "I am not responsible for his whereabouts, but I'm sure he is working very hard."

Clegg later on told Sky News he could not have shown up alongside Cameron as he completely disagreed with the veto, but he played down talk of a coalition break-up: "The coalition government is here to stay. On Europe, what I’m going to do is this – build bridges, re-engage, and make sure that the British voice is heard at the top table in Europe."

No Thatcher

When asked by one of his own Conservative MPs how he was thinking of proceeding with what eurozone leaders and the other nine non-euro countries call an "objective" to incorporate the new treaty into EU law, Cameron repeated his argument that EU institutions will not be able to fully back this new arrangement which "cannot cut across existing treaties."

On the UK being marginalised from EU decision making, Cameron said his government is still able to have enough allies to push for an EU budget freeze and to play a leading role in defence policy.

But all his arguments foundered when asked why he did not live up to the standards set by his Conservative predecessors Margaret Thatcher, who signed up to the Single Market Act and negotiated the British rebate, or John Major, who agreed to the Maastricht treaty with several opt-outs.

"I couldn't get a treaty with the necessary safeguards that's why I had to say no to it," Cameron admitted.

As for the actual time spent on discussing and preparing the summit with other leaders, the British Prime Minister said he went to Berlin three weeks ahead of the European Council and to Paris on the week before and had phone conversations with other leaders.

"There were good prospects for a deal, clearly they would have wanted a deal at 27. But they didn't want to give the safeguards - which were rational, reasonable and relevant - so I had to say no," he insisted, adding that leaders need to say no from time to time to make their negotiations credible.