Support for the war in Iraq has slumped amid escalating violence over the last month, according to an ICM poll for the Guardian.

Of those questioned, 48 per cent said that military action was not justified, while two thirds have little or no confidence in America's handling of the situation.

Forty two per cent believe Blair should bring the troops home and overall backing for the war has slipped from 53 per cent in January to 41 per cent today.

It comes as a new book by renowned Washington Post reporter Bob Woodward claims that Britain was a "driving force" in the war.

The prime minister was asked three times whether he would like to keep British troops out of the region, all of which he declined, it alleges.

The poll shows that Labour still has a five-point lead over the Conservatives of 38 per cent to 33 per cent. The Liberal Democrats are on 22 per cent support.

However, Tony Blair's personal rating remains low at minus 20 points.