Tony Blair has been warned that he should listen to the message sent by voters in Thursday's local election.

The prime minister arrived back in Number 10 on Saturday after attending Ronald Reagan's funeral in Washington on Friday.

He was greeted on his return by newspaper headlines setting out the scale of the defeat Labour suffered in the local elections.

With results declared by 165 of 166 councils, Labour had lost 464 seats, while the Conservatives had gained 263 and the Liberal Democrats were up by 132.

Speaking to BBC Radio 4 on Saturday, former foreign secretary Robin Cook said there was no doubt that Iraq was the cause of the defeat.

"The kicking was to send us a message and what we need to do is to show that we have heard that message," he said.

"That message from many of those who withheld their votes from us but would like to vote Labour in the general election...was that they were very unhappy about what happened with the war and they want to be sure that if they support Labour they are not giving a blank cheque for it to happen again."

Cook added that the party's core supporters want to know that the government would not do "the same again" if it wins the next general election.

"We should never get ourselves involved in a war against the backing of the United Nations and in order to support an American president who is deeply unpopular in Britain," he warned.

"Tony Blair needs to convey that he understands that and that he won't do it again.

"It's not enough simply to say we are holding our nerve and seeing it through."

With a renewed focus on his leadership, the prime minister admitted that "lessons had to be learned".

"Of course it's a difficult time, and these things happen to governments, but the basic commitments we have made we are delivering," he said in Washington before departing for the UK.

"The fact that the government loses council election results doesn't really augur much for the general election."