Britain caught between Nato and EU as Rumsfeld flies in

The Government was last night battling to calm American fears over its deal on European Union defence, ahead of the arrival of Donald Rumsfeld, the US Defence Secretary, in Brussels today for talks at Nato.

A controversial package of measures on defence dominated a meeting in Naples which backed plans for an EU foreign minister, and heard calls for the main issue blocking a deal on a new European constitution to be fudged.

Although it was hailed as a "breakthrough" by France, the text of the defence deal between London, Berlin and Paris has still not been agreed, apparently because Washington has not given the UK the green light to sign up.

Under fire from his critics at home, Jack Straw, the Foreign Secretary, insisted that the plans to build up Europe's defence capabilities would not undermine the transatlantic military alliance.

Mr Straw insisted that he was a "100 per cent signed-up Atlanticist", describing Tony Blair as "200 per cent". But it was clear that American objections could still wreck the deal struck by senior officials in Berlin last week. The Foreign Secretary said: "There is a process of discussion to take place with our partners. This has to be done on a consultative basis."

Colin Powell, the US Secretary of State, was reported to have telephoned two EU ministers during the talks at Naples, though Mr Straw said he had last spoken to Mr Powell on Thursday. However it will be Mr Rumsfeld, the Pentagon hawk, rather than the doveish Mr Powell, who will present the main obstacle to the deal under which the EU would gain an operational military planning cell for the first time.

Leaks of the agreement in the French press suggest Franco-German plans for a separate HQ will be scrapped. But the French Foreign Minister, Dominique de Villepin, added to the confusion when he said that details were still be discussed and he hoped for the "most ambitious solution".

At their meeting yesterday, the Italian presidency of the EU laid down ground rules under which groups of countries will be able to engage in closer defence co-operation, if they have the capability, by 2007, to intervene in operations of up to four months' duration.

Mr Straw claimed that any one of the 25 present and future EU nations would have veto on the launch of a mission by the smaller group. But that interpretation did not appear to be borne out by a new protocol circulated by the Italian presidency last night.

The meeting failed to solve any of the key outstanding issues which are blocking agreement on the constitution, due to be finalised at a summit on 12-13 December. But it moved several steps closer to a series of likely compromises and backed a plan for an EU foreign minister combining the roles of Javier Solana, the foreign policy representative appointed by member states, and Chris Patten, the European Commissioner for external relations.

The UK still objects to the term "foreign minister" but the weakness of his opposition was illustrated by the fact that Mr Straw used the term himself. The big blockage rests with Spain and Poland which have both rejected proposals to abolish member states' weighted votes in EU decision-making, agreed in Nice in 2000, which favour them disproportionately to their population size.

Mr Straw pressed for a delay on a decision on a new system, because the 2000 Nice Treaty voting plan is legally bound to stay in place until 2009. He argued: "It's only 2003 now, why do we have to have an unnecessary argument about this? Why not have a rendez-vous clause [delaying the decision until a later point] for somewhere closer to 2009, and in the light of experience we can then decide whether Nice is working or it's not working." His suggestion that this plan was being floated by the Italian presidency drew a rebuff from Italy's foreign minister, Franco Frattini. He said: "We have not spoken in terms of a rendez-vous clause. That would be totally mistaken." But he did say that, with the system being in place until 2009, "there will be a chance to see whether it works".

Germany is determined to get a deal on a new system outlined in the draft constitution under which decisions would need the support of 50 per cent of countries representing 60 per cent of the EU population. But Germany's Foreign Minister, Joschka Fischer, said he left Naples "more concerned" about divisions. "There is the question whether the enlarged Europe will meet the challenges or fall back."