Politics - John Kampfner admires Jack Straw's game plan

There is a bull market in Jack Straw shares: the Foreign Secretary has become a political force. Wil

At his cabinet meeting on 22 April, Tony Blair apologised briefly for his handling of the U-turn on the European constitution. Then he paused, and added that he would prefer to confide in his senior colleagues without them later briefing the media. Everyone knew who he had in mind.

Blair is feeling sore towards Jack Straw. He accepted the Foreign Secretary's argument about the need to change policy on the constitutional referendum, but, as one of the Prime Minister's aides put it: "Jack has not been shy about trying to take the credit for it."

Straw has become a political force to be reckoned with. The transformation has been sudden. He was promoted to the Foreign Office - to his and everyone's surprise - after the June 2001 election, with the sole purpose of executing the Prime Minister's will. After Robin Cook's tenure, Blair wanted fewer fireworks with Gordon Brown, especially over Europe. It was hoped that Straw would be a safe pair of hands.

The top mandarins in King Charles Street were resigned to seeing the Foreign Secretary having to walk across the road to Downing Street for meetings with Sir David Manning, Blair's foreign policy chief, and not the other way round. Straw did not appear too resentful. After all, that was how things were done.

As he found his feet, so he began to stake out his own positions. The list of differences with Blair is long and significant. On the EU, Straw coined for himself the description "practical European" - not for him the high rhetoric on integration. On Israel and the Middle East, he has differed sharply, preferring a far less accommodating approach to Ariel Sharon. On the US, in his almost daily phone calls to his counterpart, Colin Powell, he has lamented the direction of Bush's policies in a way Blair and his people would not dare.

On Iraq, Straw has never been comfortable. He watched helplessly as Blair and Bush secretly agreed their agenda for war early in 2002. The failure to secure a second UN resolution caused him no little soul searching. His last-minute note to Blair on the eve of war, suggesting that UK forces not be sent into combat, came as no surprise to those in the know at the top in Downing Street and the Foreign Office.

Blair peremptorily dismissed Straw's concerns, giving him a choice - either to quit or to fall in behind. He chose the latter. Even then, he was unhappy about the lack of postwar planning for Iraq.

Last July, Straw briefed the BBC that weapons of mass destruction would probably not be found - a full six months before Blair was forced to admit the same. No 10 was not pleased with him, but let the matter rest there.

Straw's increasing assertion of greater autonomy has gone down well at a Foreign Office resentful of being sidelined by a coterie at No 10. The public letter by 52 former envoys on 26 April struck a chord among some serving diplomats. One suggested that it was a "timely reassertion of the wisdom of the professionals". Straw's positioning has been shrewd. He has rarely been off the airwaves, the loyal servant advocating the government's position, but usually with his own little twist.

The more difficult the overall situation for the government, the more assiduously has Straw nurtured alliances. Truce between the Foreign Office and the Treasury quickly became full-blown peace, but the extent of his closeness to Brown will rest on the two men's ambitions. Straw has, in spite of his incessant foreign trips, vigorously worked his constituency, the Parliamentary Labour Party and opinion-formers in the media.

In Downing Street, Straw's European intervention - the manner more than the content - is seen in the same light as Brown's personal challenge to Blair at the party conference last September. Blair's allies have taken to quoting Barbara Castle, who once said she acquired Straw as an adviser to make use of his "low political cunning". Blair's core supporters in the PLP - Peter Mandelson, Alan Milburn and Stephen Byers - are doing whatever they can to rally round their man. And yet their article in the Guardian, with its barbed warning to Straw, had a distinctly plaintive tone.

For the moment, Straw is content. The Murdoch papers, where favour is most sought, are on his side. On 23 April, the Times carried a front-page story, an interview and a leader article extolling his "ruthless pragmatism". Straw had emerged as an "unusually pivotal player in both domestic and foreign policy". It compared his debating skills favourably with Michael Howard's. It suggested that he would make a most effective deputy to Gordon Brown as prime minister . . . and then it suggested that Straw could end up the "king rather than the prince".

There is a bull market in Straw shares. It is in this context that his actions of the past fortnight should be seen.

Blair's Wars by John Kampfner is published in updated paperback in June