UP to 500 jobs are at risk after the surprise closure of a civil engineering company yesterday.

The O'Donnell Brothers group, which employs about 200 staff in Billingham, on Teesside, and about another 300 in Newcastle, is believed to have gone into administration.

Staff who turned up for work in Newcastle found the gates to its Lemington depot locked.

Union leaders said they had tried and failed to contact the family firm's owners, at both its Lemington works and the site on the Billingham Reach Industrial Estate site.

Tom Ross, senior organiser with the GMB union, said: "It is absolutely devastating for the workers.

"Their future now is very uncertain."

Mr Ross and Jackie Woodall, his GMB counterpart on Teesside, will try to speak to managers at both depots again today.

Mr Ross said: "I have attempted to make contact with the company, both personally and through e-mail.

"I am prepared to meet them anywhere, any time to discuss saving these jobs and am hopeful they are going to respond."

An insider said workers had been asked to return all vehicles and equipment to the Tyneside depot last Friday for an audit.

Staff then received letters on Saturday, saying the company had gone into administration.

No one could be contacted at the company last night.

It is believed that administrators will arrive on site today.

O'Donnell Brothers carries out utilities contracts and a range of civil engineering work, including installing town centre closed-circuit television systems and street lighting.