Van Rompuy: EU could avoid full treaty change via legal trick

Instead, so long as EU leaders unanimously back a redrafting of a single protocol, the changes can be achieved almost instantly, following consultations with the European Central Bank and the European Parliament, both of which would be formalities.

The article (Art. 126) in the treaty that deals with excessive deficits is fleshed out in a protocol attached to the legal text of the document but which remains separate from the treaty itself.

This article also gives the premiers and presidents the ability to change the attached protocol without having to go through the normal procedures associated with a treaty change.

The EU rulebook normally requires that ahead of any treaty change, a full intergovernmental convention be convened, involving national governments and the European Parliament, which last week issued a demand that any treaty change pushing through advanced economic integration be accompanied by deepening democratic controls at the EU level.

Some states, such as Ireland, would likely have to hold referendums over any further transfer of powers to the EU.

Dublin is still smarting from an unexpected defeat in its 2007 referendum on the Lisbon Treaty, a defeat that was overturned the following year after the country was forced to re-run the referendum.

The Irish government is convinced that another such referendum would be lost decisively in the current economic-political climate and at a time when the country has in effect abandoned sovereignty over fiscal policy to the EU and the IMF.

Polls put opposition to a fresh treaty change on 48 percent in the country against 27 percent in favour.

Whether Van Rompuy's trick will be sufficient to avoid triggering a referendum in the country remains an open question, depending on the scale of transfer of existing powers.

Some of the changes envisaged dovetail with those outlined in the past few days by France and Germany that push for deeper economic integration in the eurozone.

Under the plan, the European Commission would be given the power to impose austerity directly on bail-out nations. Those states that flouted debt and deficit rules potentially could have their voting rights in the Council suspended.

Member states would also introduce "golden rules" requiring balanced budgets into national legislation.

The eurozone's rescue fund would be awarded a bank licence in order to borrow from the ECB and labour laws, while pension systems and other social protections would steadily be harmonised.

Meanwhile, UK Prime Minister David Cameron has said that he will veto any new treaty if he does not win protections for the City of London, the British financial district.

"As long as we get those, then [a] treaty can go ahead. If we can't get those, it won't," he told the Press Association newswire in an interview.