Tony Blair and George W Bush had signed a "secret deal" to topple Saddam Hussein a year before the US and Britain invaded Iraq, a former high-ranking British diplomat has revealed.

According to Sir Christopher Meyer, UK's Ambassador to the US in the run-up to the Iraq War, an agreement to aim for "regime change" was reached between the then British Premier and President Bush during a private meeting at the latter's Crawford ranch in April 2002 in the absence of their advisers.

"To this day I am not entirely clear what degree of convergence was, if you like, signed in blood at the Crawford ranch. They weren't there to talk about containment or even strengthening sanctions," 'The Times' quoted him as saying.

In his deposition to the British inquiry into the Iraq War, Sir Christopher also said that Blair would have been more influential if he had attached more conditions to the British support to the US-led invasion.

"I think that would have changed the nature of American planning. By the time you get to the end of the year it's too late. I did say to London that we were being taken for granted," he said.

Sir Christopher's claims came a day after the inquiry heard that Blair knew Saddam Hussein did not have weapons of mass destruction ten days before he ordered invasion of Iraq.

"I think on March 10, get a report that chemical weapons might have remained disassembled and Saddam hadn't yet ordered their assembly. There was also a suggestion that Iraq might lack warheads capable of effective dispersal of agents," Sir William Ehrman, the Foreign Office's Director General of Defence and Intelligence at the time, said.