A new book claims that Tony Blair was offered three chances to keep British forces out of the war against Iraq.

"Plan of Attack" by journalist Bob Woodward reveals that during a telephone conversation with the prime minister, President Bush asked him three times if he wanted to keep the UK out of the war.

"I would rather go alone than have your government fall," Bush is quoted as saying.

However, Blair is said to have insisted that the UK would be involved.

"I understand that, and that's good of you to say.  I said, I'm with you," he's quoted as replying.

Meanwhile, newly-elected Spanish prime minister Jose Luis Rodriguez Zapatero has ordered the withdrawal of his troops from Iraq.

As violence continued over the weekend, he said his government would "do what is necessary for the Spanish troops stationed in Iraq to return home in the shortest time possible".

Downing Street insisted that the announcement came as no surprise to Tony Blair, while a senior US State Department official played down its significance.

"This is not unexpected," he said.  "We recognised they were going to do this."