Four people have been found guilty of aggravated trespass at an anti-arms demonstration.

The case was the first of five trials which follow arrests at a protest outside EDO MBM Technology in Home Farm Road, Moulsecoomb, in June last year.

Demonstrators clashed with police at the gates of the factory, which campaign group Smash EDO says manufactures weapons components used in illegal military action in the Middle East.

Windows were smashed and walls were daubed with slogans after protesters broke through police lines.

Ugly scenes followed as officers used dogs, pepper spray and batons to clear the entrance to the factory.

The event was the first in a series of large-scale protests to bring parts of Brighton to a standstill.

A similar demonstration was staged in October and earlier this month several hundred people marched through the city centre.

Organisers have controversially refused to provide information for police about the routes they plan to take at the events.

Elijah Smith, 42, and Robert Alford, 29, both of Brigstock Road, Bristol, Eugene Saltis, 20, of Park Crescent Road, Brighton and Andrea Peng, 26, of Atkins Road, Balham, London, were convicted of aggravated trespass at Brighton Magistrates’ Court yesterday.

Smith was also found guilty of obstructing police and failing to appear in court.

He received a total fine of £300.

Alford and Saltis were also found guilty of criminal damage. Alford received a £150 fine and Saltis was sentenced to 80 hours’ community service.

Peng received a conditional discharge. She was found not guilty of criminal damage.

DCI Adam Hibbert said: "Today's sentencing sees the conclusion of the first of five trials involving thirteen defendants arising out of the June 4 2008 demonstration and represents a positive initial judicial outcome."

Eight people are also awaiting trial accused of conspiracy to commit criminal damage at the factory in January.

Computers and filing cabinets were hurled through top-floor windows in a break-in which police said caused camage worth £250,000.

Seven men and one woman are expected to stand trial later this year.