Attorney general Lord Goldsmith has been asked for a legal opinion by next month on whether or not United Nations (UN) security council approval would be necessary, according to The Sunday Times.

The newspaper says Ministry of Defence and the Foreign Office legal advisers are divided on the issue.

Chief of the defence staff Admiral Sir Michael Boyce is thought to have questioned defence minister Geoff Hoon about the legality of an attack and the potentially high numbers of British casualties, The Sunday Times reports.

If the Iraqis conclude an invasion by someone is inevitable then they might conclude it is not very meaningful to have inspections

UN chief weapons inspector Hans Blix

Intelligence service MI6 has also been asked to review the latest findings of the international investigation into Iraqi president Saddam Hussein's links with the Al-Qaeda network and other terrorist groups, according to the paper.

It says the Cabinet Office will submit its findings next month.

Meanwhile chief weapons inspector Hans Blix has insisted getting his team into Iraq under acceptable terms remains the UN's only target.

"The worry they may retain weapons of mass destruction is a very important element," he told BBC1's Breakfast with Frost programme.

Hans Blix: "Eager to help"

But Mr Blix added: "If the Iraqis conclude an invasion by someone is inevitable then they might conclude it is not very meaningful to have inspections."

His team was "eager to help towards a non-belligerent solution", Mr Blix said, but Baghdad had not yet responded to requests to arrange travel and accommodation.