Organisers warn of civil disobedience if Blair ignores protest

Britain faces the threat of strikes and mass civil disobedience if the Government fails to heed what is likely to be the country's largest anti-war protest tomorrow, march organisers said yesterday.

The Stop the War Coalition (STWC) warned Tony Blair yesterday of wildcat strikes and sit-ins if war was waged against the wishes of more than 500,000 people expected on the march and rally in London. Police and organisers do not expect trouble.

John Rees, a spokesman for STWC, said: "If they start bombing, many people, even if it is their first demonstration, will think something profoundly undemocratic has happened and something wrong has happened. Those people will then feel marching is not enough."

The coalition plans a series of protests and vigils on the day of any US-led attack on Iraq. Left-wing union leaders have called for an emergency meeting of the TUC general council.

The march organisers believe that most plans for more radical direct action will fail to get off the ground at the weekend in the face of the potentially huge numbers of peaceful protesters. Train services in some parts of the country are already fully booked and people said they were struggling to find seats on coaches to take them to the protest. Nearly 40 coaches have been booked to come from Devon, compared with only six at the last Stop the War demonstration in September. STWC says more than 200 coaches will be coming from Birmingham alone.

Police raised their estimate of those likely to attend to 500,000 yesterday after saying earlier in the week that they were expecting not much more than half that number. Extra toilets have been set up in Hyde Park, where the rally will be held, and London Underground has warned that stations in the city centre could be closed because of the large numbers.

"I am not quite sure if it will be a demonstration in the normal sense," said an STWC spokesman. "With London cordoned off by police, it may look more like an occupation force in the centre of the capital city than a formal demonstration."

Demonstrators and police said they did not expect disruption because of the heightened state of security in the capital, but the crowds mean the heart of London will in effect be closed to traffic and buses will be unable to pick up passengers in the centre. Some events are planned by other organisations to coincide with the main rally and march.

After the rally at Hyde Park, where speakers will include Jesse Jackson and Charles Kennedy, a mass sit-in is planned at the Eros statue in Piccadilly. Other direct-action websites have included notice of a demonstration in Grosven-or Square, near the American embassy, to "make clear our feelings about the agitators behind the drive to war".

Scotland Yard warned that the march would stretch the force but far fewer officers would be on duty than on previous anti-capitalist demonstrations because of the lower threat of violence.

Millions of people are expected to protest in hundreds of cities around the world on the same day. Up to 100,000 people are expected in New York, where Archbishop Desmond Tutu will address a rally.

Weekend demonstrations are also planned across Australia, where the government has joined Britain and the United States in committing troops to a possible war.

The Government was accused yesterday of the "worst kind of anti-democratic control-freakery" by attempting to silence the voice of Scottish anti-war protesters at Labour's spring conference in Glasgow, where the Prime Minister will speak. In the House of Commons, Pete Wishart, the Scottish National Party MP for North Tayside, called for a debate on "free speech" because of a ban on the use of sound equipment outside the conference centre. But organisers expect the dispute to be settled by tomorrow, when 40,000 people are expected for the protest.