UNION members at Asda depots in Washington and Teesside will be balloted in a row over collective bargaining and pay, it emerged yesterday.

The GMB union said its members at 21 distribution depots and warehouses across the country will take part in the voting from next month.

It said Asda had appealed against an employment tribunal decision to award £2,500 compensation to hundreds of workers - including many at the Washington depot - in a dispute over union rights - which could cost Asda, part of the US Wal-Mart empire, up to £850,000.

Michael Hopper, of GMB, said: "This shows that Asda cannot accept the judgement of an independent panel about its anti-union activities.

"The decision to appeal will spur GMB members to vote yes for strike action to secure proper bargaining rights."

Last month, Asda opened its £30m import centre at Teesport, to receive non-food goods for stores all over the country - a move which is creating 450 jobs.

Mr Hopper said any GMB members at the depot would also be balloted on strike action. Some of the workers there have been transferred from the Washington depot.