As foreign affairs enter the debate, so the anti-war protesters make their voice heard

Six people were arrested last night after police clashed with protesters in fractious scenes in Bristol hours ahead of the second leaders' debate.

The dramatic scenes were the climax of an increasingly tense afternoon that saw anti-war demonstrators clash with riot police.

Gordon Brown was hit by a chorus of booing as he arrived outside the Arnolfini arts centre in Bristol, the location of the debate that authorities had unsuccessfully attempted to keep under wraps from the public ahead of the broadcast.

The 150-strong crowd that gathered during the day comprised numerous groups including anti-capitalists, Palestine campaigners and a small number of English Defence League (EDL) activists. With the arts centre cordoned off, demonstrators grouped on the other side of the river from the venue.

Eyewitnesses reported seeing EDL members hitting television cameras and shouting. Placards and banners were waved with slogans scrawled including: "stop the war", "troops home" and "Bankers, politicians, fat cats, we won't pay for their crisis". Riot police with shields and horse-mounted officers were seen scuffling with protesters.

A spokeswoman for Avon and Somerset Police said later that six people had been arrested for public order offences. She said: "We had planned for peaceful protests and there have been multiple protests in a number of locations across the city.

"They have been largely peaceful and compliant with our requests."

Nick Clegg, the Liberal Democrat leader, was the first to arrive. The Conservative leader David Cameron arrived around 15 minutes later accompanied by his wife, Samantha.

The most hostile reception was saved for the Prime Minister. As he got out of his car, the jeering escalated and demonstrators goaded him over megaphones.

As the debate began inside the building, the crowds began to wonder off. Only a few protesters remained after 8pm. Earlier in the day Bristol Stop the War activists had distributed pamphlets alerting protesters to the location of the debate. "Unless it is an elaborate diversionary tactic, it looks certain that the Arnolfini is the venue for the televised debate between Brown, Cameron and Clegg on Thursday.