Police have moved in to clear tents from London's Parliament Square, which has been a focus for protesters campaigning on issues including the war in Afghanistan.

The Metropolitan police said that officers had arrived on the scene at around 7.30pm on Monday to remove "all tents and sleeping equipment".

The move comes after the passing of the police reform and social responsibility bill, for which the home secretary had created an amendment that outlawed the setting up in Parliament Square of "any tent, or any other structure that is designed, or adapted … for the purpose of facilitating sleeping or staying in".

Protesters – led initially by the late peace campaigner Brian Haw – have occupied the pavement opposite the Houses of Parliament for about a decade and set up "Democracy Village" on the green in May 2010.

They were evicted in July last year by the Greater London Authority following a high court order, but some protesters then pitched tents on the pavement next to the lawn.

As word of the police operation spread, calls for a counter-protest in the square were put out on Twitter by activists including Occupy London protesters camped outside St Paul's Cathedral.

A police spokesman said shortly after 10pm that the operation was ongoing and that no arrests had been made.

Equipment was being loaded into marked lorries by workers from the City of Westminster Council, which proposed a new bylaw in December that would impose £500 fines on anyone failing to remove their tent.

The leader of City of Westminster council, Colin Barrow, said that he welcomed the police action "to return Parliament Square to open public use".

"For too long local people and tourists have been unable to fully enjoy the square," he added. "This is a tragedy and the sooner this historic site can be enjoyed by the public, the better. Westminster Council is currently pursuing a bylaw to ensure we can manage the area for everyone. The police action follows the clear will of the people, expressed through Parliament, to remove this encampment."