Up to 12,000 Asda employees face the sack next week if they refuse to sign a new contract that will reduce their pay and benefits.

Basic hourly pay will be increased but staff will lose all paid breaks and premium pay will be cut on most bank holidays. In addition, the number of hours classified as better-paid night shifts will be reduced.

The contracts, which will apply to more than 100,000 employees that are paid hourly, will also require workers to accept variable shifts between 8am and 10pm and switch between departments as required.

In August the Leeds-based retailer told staff that if they refused to sign the new contract, they would have to leave the company on 2 November.

GMB, the union for Asda workers,has written to company bossescalling on them not to sack affected workers.

In an open letter to senior vice president Hayley Tatum, GMB asked the retailer to withdraw its threat, and last week Asda workers handed in a 23,000-strong petition opposing the contract during a mass protest in Leeds.

The contract changes come after Asdagroup’s profits rose by 13 per cent to £805 million last year, while pay to directors increased from £9.5m to £12m.

GMB national officer Gary Carter said:“If Asda is serious about not wanting to sack thousands its employees on the run up to Christmas, they need to withdraw the dismissal notices and sit down with GMB to resolve this dispute.

'Asda has served notice on up to 12,000 of its loyal employees – that cannot be right. The onus is now on them tosave people’s jobs with a better deal that their employees can sign up to.”