Beneath a floodlit Lord Nelson in Trafalgar Square, the author of A Brief History of Time read the names of Iraqi civilians who had died and explained why he had come to London to be part of the reading.

"The war was based on two lies," he said through his voice synthesiser. Both the claims of weapons of mass destruction and linkage to September 11 had proved untrue. "It has been a tragedy for all the families. If that is not a war crime, what is?" He added: "I apologise for my pronunciation. My speech synthesiser was not designed for Iraqi names."

The reading, organised by the Stop the War Coalition, was one of hundreds taking place all over Britain and in other countries, including Italy, Spain, Switzerland, Australia and Iraq. More than 5,000 names were read out in front of hundreds of anti-war campaigners and passers-by

Ken Livingstone, the London mayor, said that the US election day had been chosen as the appropriate day for the event. He recited the names of Iraqi children who had died.

Chris Eubank, the former world middleweight boxing champion, read the names of British soldiers. Among those also reading names were writer Harold Pinter, actors Neil Pearson and Corin Redgrave, MPs Jeremy Corbyn and George Galloway and American students who opposed the war.

Last week, the Stop the War Coalition estimated that more than 25,000 people had been killed in the conflict. However, that number has now been revised in the wake of the publication in the Lancet of a survey indicating that the number of deaths attributed to the war could be as high as 100,000. The names read out ranged from British Lance Corporal Matty Hull and Iraqi children to Thai servicemen.