Engineers at British Gas are starting the first of five strikes in protest at the closure of the company’s final salary pension scheme to new entrants.
The engineers are holding a 24-hour strike, with further ones planned for 19 and 21 December, and 6 and 9 January.
A total of 6,000 workers, who are members of the GMB union, are taking part.
At the weekend, British Gas management said they were “disappointed and frustrated” after a breakdown in talks.
The union said it had asked the company to suspend closing the pension scheme to new entrants for a year while the scheme was re-evaluated.