Short aims to run as Brown's deputy in leadership contest

Clare Short, the International Development Secretary, is preparing to run as Gordon Brown's deputy in the Labour leadership contest when Tony Blair steps aside.

Ms Short has indicated that she wants to take on the combined post of Deputy Prime Minister and Foreign Secretary if the Chancellor becomes leader, government sources have revealed.

The plan has infuriated Blairite ministers, who seized on it yesterday as further evidence of an orchestrated plot to undermine Mr Blair.

The row blew up as Mr Brown was questioned for the first time in months about his reportedly fraught relations with Mr Blair and his ambitions to become Prime Minister. Amid fresh speculation in Westminster of increased tensions between the two men, he was asked if they were good friends. "Absolutely, we get on very well together," he told BBC Radio 4's Today programme.

When asked if he wanted to be Prime Minister, Mr Brown replied: "That's not, er, a question that interests me. What I'm wanting to do is to get on with the job of being Chancellor."

John Reid, the Labour chairman and a staunch Blair supporter, added later: "As regards speculation on the future prospects of any of us, that is a very hazardous thing to do. The Chancellor is absolutely forthright in his view that he's not interested in that speculation."

Blairites in the Government have become increasingly resentful of the Brown camp in recent months, with clear tensions over a range of issues such as foundation hospitals, university top-up fees, pensions and specialist schools. Crucially, Ms Short gave an interview in which she said that top-up fees were "a really bad idea".

One Blair ally told The Independent: "When you look at this, with Gordon letting it be known that he is opposed to top-up fees, Clare going on the record about them, the criticism of foundation hospitals, and now Clare lining herself up like this, it looks like they've got a real operation under way."

The International Development Secretary has consistently won large increases in her budget from the Treasury and in the pre-Budget report gained another £65m aid fund for the world's poorest nations. She and Mr Brown also developed a close relationship over moves to get debt relief on the international agenda.

Relations between Number 10 and Number 11 are understood to be "the worst for a long time", insiders say. Some ministers suspect that attacks by Frank Dobson, a former health secretary, on the danger of "elitist and two-tier" public services are part of a wider campaign by the Chancellor.

Mr Brown himself warned his colleagues to beware of the "limits" to marketisation of public services at this month's political cabinet meeting. But Blair allies believe that genuinely radical change is needed to persuade the public that key state services can deliver.

A Brown leadership campaign would be sure to count on the support of Alistair Darling, the Transport Secretary, and Andrew Smith, the Work and Pensions Secretary, as well as Ms Short.

Brownites still resent the fact that Mr Blair outmanoeuvred Mr Brown before the 1994 leadership contest. Some claim that Mr Blair began his campaign before John Smith's funeral, an allegation vigorously denied by the Blair camp. One Brown ally said: "We were caught out last time. We will not be caught out next time."

As a result, the Chancellor has been assiduous in keeping in touch with colleagues in the Commons tea room, writing to new MPs and encouraging their more senior colleagues. He has seen putative challengers such as Jack Straw, David Blunkett and Charles Clarke all come and go and remains the overwhelming favourite among MPs, trade unions and party members.