LONDON, Sept 18: Britain's foreign secretary and senior officials warned Prime Minister Tony Blair a year before invading Iraq that chaos could follow the toppling of Saddam Hussein , a newspaper said on Saturday.

The Daily Telegraph said Foreign Secretary Jack Straw sent a letter marked "secret and personal" to Mr Blair in March 2002 warning that no one had prepared for what might happen afterwards.

The newspaper also said British officials believed US President George Bush had instigated war because he wanted to complete his father's "unfinished business".

"Even the best survey of Iraq's WMD programme will not show much advance in recent years," a Foreign Office policy director said.

"Military operations need clear and compelling military objectives. For Iraq 'regime change' does not stack up. It sounds like a grudge match between Bush and Saddam (Hussein)."

President Bush's father, George Bush, was president during the 1991 invasion when a US-led multinational force freed Kuwait and then drove the Iraqi army back deep into the country before withdrawing.

The Foreign Office in London declined to comment directly on the report, but said in a statement that Iraq was moving towards a democratic future for the first time.

If confirmed, the leak - which comes amid a sharp escalation in violence in Iraq - could prove to be damaging to Blair with an election looming next year. It also illustrates the depth of concern in his government to joining the US-led invasion last year.

"There seems to be a larger hole in this (post-war planning) than anything," the Telegraph quoted Mr Straw as saying.

"No one has satisfactorily answered how there can be any certainty that the replacement regime will be any better."

Blair defended his position on Saturday.

"The idea that we did not have a plan for afterwards is simply not correct," he told a news conference.

"We did and indeed we have unfolded that plan but there are people in Iraq, outsiders as well as former regime elements, who are determined to stop us. That's why it is all the more important that we carry on until we win it and we will."

The opposition Conservatives - which backed Blair over the war but later said their support was based on bogus intelligence information from his security services - said the leak revealed a lack of a comprehensive reconstruction plan.

"The assurances given to us by both the prime minister and Jack Straw that such a plan was in hand were clearly misleading," the Conservatives' foreign affairs spokesman Michael Ancram said on Saturday.

The Telegraph also said that senior ministerial advisers warned in a "Secret UK Eyes Only" paper that success would only be achieved if the United States and others committed to "nation building for many years".

"The greater investment of Western forces, the greater our control over Iraq's future, but the greater the cost and the longer we would need to stay," it said.

The foreign affairs spokesman for Britain's third political party, the anti-war Liberal Democrat's Menzies Campbell, said, if accurate, the letters provided a "devastating insight" into the political runup to the invasion.

"The British government has not come clean and been frank with the British people, either about regime change or the long term troop commitment which would result if Saddam was removed," he said. -Reuters