A ring of steel will be erected around Belfast's courts district on Tuesday morning as Northern Ireland holds its first terrorist supergrass trial in a generation.

Riot police are on standby and separate courts will be opened to keep rival factions apart in preparation for the appearance of two self-confessed members of the Ulster Volunteer Force (UVF), who will give evidence against former loyalist comrades.

Fourteen alleged UVF activists face 97 charges ranging from murder to blackmail. The accused belong to the notorious Mount Vernon UVF, a North Belfast terror unit heavily infiltrated by police special branch.

The trial will hear accusations that some of those charged with the murder of the rival Ulster Defence Association (UDA) member Tommy English in October 2000 were police agents at the time of the killing. English was murdered at his home in Newtownabbey during a UVF-UDA feud that erupted on Belfast's Shankill Road two months earlier.

The man accused of killing English is Mark Haddock, one of the alleged leaders of the UVF in north Belfast. Haddock was himself targeted by his own terror group after he was unmasked as a special branch informer. Until last week Haddock had been living at a secret address in England under a court order that banned the media from identifying his location. He flew back to Northern Ireland from England on Friday and has since been held in custody.

The bulk of the evidence against Haddock has been supplied by David and Robert Stewart, brothers who are serving a prison sentence for aiding and abetting the killers of English. The pair agreed to turn state's evidence in return for reduced jail sentences.

Security sources in Northern Ireland told the Guardian that the police fear the UVF may stage violent protests across Belfast in the hours running up to one of the biggest trials since the controversial supergrass hearings of the 1980s. In June the UVF orchestrated three days of sectarian rioting in east Belfast after mounting an organised attack on the Catholic enclave of Short Strand.

Police in Northern Ireland are so concerned about potential trouble that they and the courts service have set up a unique arrangement for relatives of the accused and families of their alleged victims to watch the opening day of the case. Friends, supporters and relations of the alleged UVF gang will be allocated a court a short distance from the main courthouse where the trial will be held.

Loyalists have already staged protests against the trial, which they claim is solely based on the evidence of "paid perjurers", a phrase the UVF used in the 1980s against a number of witnesses in the supergrasses trials that put dozens of loyalists in prison.

Banners have been slung across main routes into loyalist districts from a new organisation called Families Against Supergrass Trials. The group has accused police of double standards, claiming investigations are focused on loyalist rather than republican past crimes.



At the height of the first supergrass trials between 1982 and 1985, 25 men turned state's evidence. Loyalist and republican informers put hundreds of suspects behind bars for dozens of murders. In the case of IRA supergrass Christopher Black, 22 of his former comrades were jailed for more than 4,000 years between them.

But the system collapsed in 1985 after a judge ruled that another informer's testimony was "unworthy" and almost all of those who had been held on remand were freed.