Leading article: Walk right in

It was less than a year ago that President Bush "dropped by" on Gordon Brown, then still Chancellor, while the latter was having talks with a senior administration figure in the White House. Now, apparently, the same procedure of a non-official presidential descent is being planned for David Cameron's expedition to Washington this week.

It's a nice ruse, this tactic of "spontaneous" dropping-by, enabling the US president to show warmth while not getting involved in official approval. And in this case it suits both parties. Bush, having famously dismissed the present leader of the British Conservative party as "never heard of him" at a time when the Tories were persona non grata in Washington for their distancing over Iraq, has almost certainly been told about Cameron now. Like the Murdoch press, the White House likes to back a winner, whatever it thinks of him personally.

Cameron will be just as calculating. For him there is no longer much percentage in backing. a president who will be out of office by the time that the British election comes around. An informal chat now, a demonstration that he's a player in Washington while not associating himself too publicly with Bush himself, is just the ticket .

You can see the advantages of the "drop-by", even over here. If only King Abdullah of Saudi Arabia could have come to visit the Regent Street Mosque and the Queen and Gordon Brown dropped in on him after prayers, or Robert Mugabe could visit Portugal next week in a private capacity, and the British Prime Minister "accidentally"bump into him in a bar listening to fado.

How much easier diplomatic life would be.