The two leaders, dogged by questions about their justification for invading Iraq, meet today to reinforce their special relationship strained by postwar chaos and intelligence failures.

"We have no closer ally than Great Britain," said White House spokesman Scott McClellan. "The prime minister is a strong leader who is a great friend of the American people and we have stood together to advance peace security and freedom."

Blair is under intense attack at home for the failure to find Saddam Hussein's suspected weapons of mass destruction, cited by both countries as the main reason for going to war.

Blair will address a joint session of Congress before his White House visit on Thursday. The last Prime Minister to do so was Margaret Thatcher in 1985.

The close relationship has been tested by a rift over a disputed allegation that Saddam sought uranium from Africa. Bush has cited information from Britain for the charge, although he says it can't be backed up by US intelligence.