British Gas engineers will launch a fresh wave of strikes on Friday in a deadlocked dispute over pay and conditions.
Members of the GMB union will walk out for four days following weeks of action since the start of the year.
Parent company Centrica on Thursday announced that its underlying earnings had fallen by almost a third as it lost more customers.
The group reported a 31% drop in underlying operating profits to £447 million for 2020.
Talks have been held between the two sides at the conciliation service Acas, but the union has accused the company of refusing to withdraw fire and rehire plans.
Justin Bowden, GMB national officer, said: “Last summer, when British Gas decided on fire and rehire pay cuts for gas engineers, it was already a profitable company – as today’s results confirm.
“So there is no need to hurt workers, customers and shareholders. Refusing to take fire and rehire off the table is the main obstacle to a settlement at Acas.
“After 22 days of strikes, more than 230,000 homes are in a backlog for repairs and 300,000 planned annual service visits have been axed.”
A spokeswoman for Centrica said: “We have plans in place to manage industrial action but we’re sorry for any disruption this is causing to our customers. We’ll continue to prioritise vulnerable customers and emergency situations.”
Centrica chief executive Chris O’Shea said about the Acas discussions: “These talks have given us the basis, hopefully, for an agreement which is being presented to our staff at the moment.
“I’m really hopeful we can move forward with the GMB in line with other unions, where we already have agreements.
“Hopefully we can move forward and put this behind us to work together to transform Centrica.
“The changes we are making have allowed us to create 1,000 new apprenticeships.
“These jobs are well-paid jobs and I’d like to create more of them, but we can’t do that on our old terms and conditions. We need to modernise the company.”