Brian Haw, the man who has been protesting against conflict in Iraq opposite the Houses of Parliament since June 2001, has been arrested.

In a police operation, officers apparently commandeered a W H Smith lorry to take away the extensive array of protest placards which Haw has erected in Parliament Square over the past three years.

Policemen from Charing Cross police station expressed concern about a suspect vehicle in the Westminster area before clearing Parliament Square at around 12.20am.

They imposed a security cordon around the square under the anti-Terrorism Act, and removed Haw and his possessions.

However, Haw's supporters are already arguing that the reasons given by the police were no more than a pretence.

Haw has long voiced the concern that the various attempts to remove him have been, and continue to be, politically motivated. He was later released without charge.

His solicitor, Michael Schwarz, said: "Brian Haw is peacefully campaigning on perhaps the most significant issue of the day at a place which is supposed to be the very heart of our democracy. 

"It is difficult to think of a more compelling example of the deployment of the rights to protest."

Haw has already had proceedings against him for obstruction of the highway, brought by Westminster Council, dismissed on the grounds that he was exercising his freedom of expression and assembly under the Human Rights Act.

Haw's supporters are currently continuing the protest in Parliament Square.