Six men who disrupted the filming of the TV show Celebrity Big Brother as part of a Fathers 4 Justice demonstration were handed fines in court last week but vowed to continue their campaign.

Eight men appeared before St Albans Magistrates, although charges against two of them were subsequently dropped.

Four pleaded guilty to disorderly behaviour and two pleaded not guilty but were convicted at the end of a two-day trial. The offences related to an incident at Elstree Film and Television Studios, in Shenley Road, Borehamwood, in January, when fireworks were launched towards the Big Brother house.

The court heard that the fireworks flew over the jacuzzi area of the set, which had a thatched roof. Some of the protesters remained outside the compound, but others were found trespassing. When confronted, Jason Hatch and David Pyke handcuffed themselves to some railings.

Hatch, 33, of Alstone Mews, Cheltenham, and Pyke, 49, of River Leys, Swindon Village, pleaded not guilty but were each fined £250 for public disorder and a further £150 for obstructing police.

They were also ordered to pay £200 each in costs and £218 in compensation to the fire service.

Sentencing the pair, Judge Geoffrey Wicks said: "This was a volatile incident during which there was much movement and noise which resulted in members of the public being harassed, alarmed or distressed.

"This is not the first time you have been involved in a demonstration which was designed to attract to yourselves and your cause the maximum publicity "I don't make any comment as to the validation of your cause. I am not proposing to make martyrs of you because your case is not one that has sufficient merit to attract martyrdom, but I also do not want to impose penalties that are trivial."

Mr Wicks said he felt the fines were significantly lower than they should have been, due to the finances of the two defendants.

At an earlier hearing, four other protesters pleaded guilty to disorderly behaviour and were each fined £250. They were: Michael Downes, 43, of Manchester; Roland Primas, 44, of Reading; Stephen Smith, 36, of Bristol; and Andrew James, 35, of Newport.

James and Primas were ordered to pay £55 costs. Downes and Smith each have to pay £100 costs.

The case was dismissed against Elaine Risk, 45, of Manchester, and Matthaus Huber, 52, of Dagenham.

Outside court, a group spokesman said: "We were not guilty of anything except highlighting the plight of fatherlessness' in this country and the treatment of fathers in the family court. We're going to continue the fight for justice even if that involves prison."