Mr Cook said last night that he would seek a divorce from his estranged wife, Margaret, to whom he has been married for 28 years so that he can marry his secretary, Gaynor Regan.
Although one Sunday newspaper yesterday suggested that his ministerial performance would be impaired, for example, in "Islamic countries or the Vatican", because he was living with another woman while still married, Mr Blair does not share that view.
Interviewed on BBC television's Breakfast with Frost, in Tokyo, Mr Blair said there was no point in crying about the diversion of attention away from his Japanese trip, but in the end the public would judge his administration on its performance on hospital waiting lists, class sizes, crime and the economy. As for Mr Cook himself, he said: "On the international stage, he has made a huge reputation for himself. I mean, that guy is doing a tremendous job for Britain. You go to these international forums and he is a key player; they listen to him, he has had a tremendous influence even before we took over the presidency of the European Union."
Mr Blair also repudiated a suggestion put out by "friends" of Gordon Brown, Chancellor of the Exchequer, that he and Mr Brown had struck a deal before the death of John Smith, in 1994, that Mr Blair would stand aside for Mr Brown to succeed to the Labour leadership.
According to a new biography of Mr Brown by Paul Routledge, political correspondent of the Independent on Sunday, Mr Brown's "friends" say he felt betrayed when Mr Blair decided that he did, after all, want to run for leadership. Even though Mr Brown felt he could have beaten Mr Blair, he decided not to stand, to save the party from the consequences of a split and a possible "dirty war". Mr Blair said in yesterday's interview that Mr Brown was one of his closest friends, " and I would not believe a whole lot of codswallop".
- Anthony BevinsReuse content