The �80m centre lay in ruins after the fire

Nearly 30 workers at the Yarl's Wood centre in Bedfordshire say they are still suffering post-traumatic stress disorder after being subject to violence from rioting asylum seekers in February last year.

The GMB union says it is suing the company in charge of the centre, Group 4, on behalf of its members who worked there as detention custody officers.

Half of the centre was destroyed by fire, but after a three-month trial costing more than �1m, no one has been convicted of arson.

Two asylum seekers were jailed for four years on Friday for violent disorder.

Group 4, which is part of the Group 4 Falck group, was branded a "laughing stock" in court, and the judge said the firm was ill equipped to deal with the violence.

'Mental trauma'

GMB senior organiser Ed Blisset told BBC Radio 4's Today programme: "We still have a large number of members off sick, following the tragic events of St Valentine's Day.

"They've suffered great mental trauma and indeed, physical injury. They're still off sick and in no fit state to return to work at present.

We did not prevent the fire service or the police service from gaining access to the site John Bates Group 4

"The GMB on their behalf is pursuing Group 4 and their insurers for personal injury damages and those cases are now ongoing."

Mr Blisset later told BBC News Online the staff involved had suffered their injuries from violent rioters, as well as jumping from burning buildings.

He said Group 4 and the Home Office were to blame for not installing sprinklers and ignoring warnings about a possible riot.

In addition, Group 4 had only provided low staffing levels, he said.

Inquiry

In response to the news of the legal action, Group 4 Falck's director of communications, John Bates, told BBC News Online: "We will obviously deal with those matters as we face them and deal with them with compassion.

"That was a very serious incident at Yarl's Wood and we instigated a programme to offer emotional and psychological support to our people, and we continue to do so."

He also denied the fire service or the police service had been prevented from gaining access to the site.

A Home Office spokeswoman told BBC News Online: "The Home Office has launched an independent inquiry into events at Yarl's Wood.

Momodou was jailed for four years

"The civil case is a matter for Group 4. If we were asked to contribute, that would be through the normal legal channels and it wouldn't be appropriate to comment further."

On the issue of sprinklers, she said advice from some fire experts had recommended no sprinklers be installed.

But following the fire, that decision has been reversed and sprinklers are being put in for the reopening, she added.

Earlier in the week, Harrow Crown Court heard that staff were forced to barricade themselves in offices from an angry mob.

Twelve men escaped and are still at large, while the centre is only partially reopening in September.

Albanian Beher Limani, 26, and Nigerian Henry Momodou, 39, were convicted of violent disorder. Three other men were cleared of the same charge.

Momodou, speaking before the conviction, told Today he was innocent and was being victimised for complaining about conditions after the fire.

Alistair Burt, the Tory MP for North East Bedfordshire, has complained the inquiry into the riot is not being held in public.