Kennedy says he will go on march

Charles Kennedy and Mo Mowlam became the latest high-profile figures yesterday to lend their support to the national Stop The War march on Saturday. Organisers expect more than half a million people to join the protest through central London.

The Liberal Democrat leader said that Tony Blair had failed to make a consistent case for war. He told the BBC: "He seems to be saying that we can, as a country, at one and the same time pursue the United Nations line, which has been our argument as a party all along, but at the same time you have President Bush saying the game is essentially up, time is gone, we have made the call and that Britain will – regardless – go along with the American administration.

"Those are not consistent arguments. They are inconsistent with each other and I think that we need more clarity from the Prime Minister. I think that is what the country wants."

Ms Mowlam, a former secretary of state for Northern Ireland, told Sky News that she was also going to join the anti-war march, insisting that she could no longer stay silent on the issue of Iraq.

Meanwhile, Mr Blair is facing a grassroots revolt from local Labour Party members. Dozens of constituency parties are expressing their anger at British policy over Iraq as members of Labour's national policy forum prepare to debate foreign affairs later this month.

One policy forum member said local constituency parties were "apoplectic" about the prospect of war, with many members threatening to give up their membership cards. Mr Blair also faces difficulties at Labour's spring conference later this month.

Kenneth Clarke, the former Tory chancellor, likened attitudes to war in Iraq to opposition to the Vietnam War. "If you go to war in modern times you need the broad bulk of the public behind you. It is a broad analogy to draw between America and Vietnam, but what destroyed America in Vietnam was that the bulk of the American public were never really persuaded of the case for fighting in Vietnam at all," he told BBC Radio Four's The World This Weekend.