Talks between Unite and London Underground (LU) in a dispute over working conditions have broken up with ‘no glimmer of hope’ of a resolution in sight, according to the union.

Hugh Roberts said if a deal cannot be agreed by Friday, about 40 technicians at the Tube’s power control room in Blackfriars Road will throw the switch, something the union says would effectively cripple the network.

“The Tube depends on electricity and our members will switch it off,” said Mr Roberts.

He said under the rules of the Office of Rail Regulation (ORR), LU managers are not allowed to touch electrical equipment unless they have the proper authorisation.

He said talks would re-start on Wednesday morning, but the clock was ticking.

“I wouldn’t want to mislead people that we are getting anywhere but we are hopeful that we will produce a solution,” said Mr Roberts.

The dispute could cripple the Tube system over the Bank Holiday weekend, says Unite, if its members go out on strike late on Friday night and do not return until Tuesday morning.

The ORR confirmed it was keeping an eye on the situation. A spokesman said: "Our inspectors will be out and about during the strike to ensure the people covering roles have the correct skills and competencies."

London Underground has not revealed how it intends to combat the walkout and keep trains running but it has said it plans to run a normal service.

More as we get it