LONDON (Reuters) – The GMB union said on Wednesday that its members at Centrica’s British Gas will start a five-day strike from 0001 GMT on Thursday.

The strike comes after GMB conducted a strike ballot of 9,000 members in December last year and 89% voted in favour of industrial action.

GMB said the strike is in response to what it called “fire and rehire” cuts to workers’ pay and terms and conditions by British Gas’ parent company Centrica.

In June, Centrica, Britain’s largest energy supplier, said it planned to cut about 5,000 jobs, almost 20% of its global workforce, and change the terms of worker contracts, as the utility stepped up restructuring in the wake of the COVID-19 pandemic.

Centrica said on Wednesday gas supplies and production will not be affected by the strike.

“We’ve done everything we can with the GMB to avoid industrial action … We have strong contingency plans in place to ensure we will still be there for customers who really need us, and we’ll prioritise vulnerable households and emergencies,” a Centrica spokesperson said.