Downing Street has played down reports that the US has requested 25,000 UK troops to join an attack on Saddam Hussein. The Observer newspaper said the troops had been requested as part of a possible ground force aimed at overthrowing the Iraqi president. "No decisions have been taken, let alone any requests made," a Number 10 spokesman said. The Foreign Office did confirm, however, a Sunday Express report that minister Ben Bradshaw this week had meetings with Iraqi opposition groups in London, and will have more in the coming week. A spokeswoman described the meetings - in which the potential for national rebellion against Saddam was reportedly discussed - as "nothing out of the ordinary".

The US has threatened action against Iraq unless it lets UN weapons inspectors back into the country - and possibly even if it does. The Observer suggested that UK Prime Minster Tony Blair was considering three options for a possible assault on Iraq:

• 25,000 UK troops as part of a 250,000-strong ground force similar to Desert Storm in 1991
• Smaller special forces units supporting opposition forces within Iraq - a tactic used with the Northern Alliance in Afghanistan
• Intensified air strikes unless a weapons inspection agreement is drawn up

Split denied
A row over the possibility of the UK joining any US attack on Iraq, as part of the war against terrorism, has been building since it was first mooted late last month. On Saturday, Labour Party chairman Charles Clarke denied widespread reports of a Cabinet split on the issue. Mr Clarke said there had been a full Cabinet discussion on the matter, but that reports of a split were "completely wrong". Mr Clarke said Mr Blair would urge US President George Bush to be cautious before launching any attack. He said Mr Blair was concerned the US should take the international community with it in any action.

"Our argument is that the US must internationalise what they are doing, work with other people in the world community. "Any action in these fields is only likely to succeed if you have got the world community united in dealing with it," he told BBC Radio 4's Today programme.

More than 70 MPs, including many Labour backbenchers, have signed a motion against military action in Iraq. On Monday, MPs Alice Mahon (Halifax) and Tam Dalyell (Linlithgow, also Father of the House), will deliver a letter to Downing Street warning Mr Blair against joining any action against Iraq. The delivery will coincide with a visit by US Vice President Dick Cheney to Mr Blair, where it is expected that the matter will be discussed.