LONDON, DEC. 24. When three ambitious and competent politicians in the prime of their political careers are forced to share the same roof, can tensions be far behind, particularly when there is an election round the corner and new turfs and pecking orders are at stake? No wonder, Whitehall is said to be full of steam with its three main occupants jostling for space in order to improve their visibility ahead of the elections and the reshuffle that would follow.

The media grapevine is buzzing with stories that the Foreign Secretary, Mr. Robin Cook, is annoyed with his two junior Ministers, Mr. Peter Hain and Mr. Keith Vaz, for speaking out of turn in a bid to grab the headlines - and often at his cost. Apparently he is furious that a formal memo which Mr. Hain wrote to him on the U.S. defence missile system was leaked to the media which went to town with it. Mr. Hain in his memo opposed the U.S. plan and warned that Britain's support to it could provoke widespread peace protests reminiscent of the Campaign for Nuclear Disarmament against cruise missiles.

The Sunday Times said sources close to Mr. Cook thought Mr. Hain was guilty of ``excessive grandstanding''. It quoted a Cook source as saying: ``You should ask why it was necessary for Peter to write a formal memo like that and how it leaked. Robin has his suspicions.'' The Cook ``camp'' perceived Mr. Hain's intervention as unwarranted, and an attempt to bolster up his ``old Labour'' base with an eye on the elections. Mr. Cook is reported to be even more infuriated with Mr. Vaz for the way he handled a Commons debate on the Nice summit. Mr. Vaz has been accused of playing the ``clown'' by his critics. He is also thought to be ``arrogant'' in his dealings with his junior officials.