Workers union GMB has claimed a victory after successfully persuading Asda to slash the proposed redundancies at its Sunderland distribution centre by more than half.

A row broke out between the supermarket and the union after Asda claimed workers affected by the cuts were temporary staff that were no longer required after the Christmas rush.

The GMB disputed this, arguing that some of those in the firing line had been employed at the distribution centre for up to three years.

“We believed the original proposals would affect those on short-term contracts to help out over Christmas,” said GMB regional organiser Michael Hopper. “But when we looked into it we found some people had up to three years’ service. So we appealed, saying we were not accepting the company’s proposal to let these people go.”

Hopper said the GMB had negotiated an agreement that only workers with less than one year’s service would be leaving, meaning just 30 from the original 70 job cuts would actually go through, and that those 30 would be first in line to return when new staff were required.

“We believe the original business plan to lose 70 staff didn’t stand up,” said Hopper. “I don’t think a lot of thought went into it.”

An Asda spokeswoman defended its initial decision: “In line with most retailers, demand for food in our stores drops in January, which means we have to review the need for temporary workers,” she said.

“We’re working with GMB to minimise the job losses.”