An employment tribunal in Newcastle-upon-Tyne found that Asda had illegally offered an inducement to 340 trade union members to give up the collective agreement negotiated by their union.
The supermarket giant was ordered to pay a total of £850,000 – a fixed sum of £2,500 to each of the 340 GMB union members involved in the inducement – last Friday (10 February) after a hearing between the 16 and 19 January.
Asda's anti-union activities were found to be in breach of Section 145B of the Trade Union and Labour Relations Consolidation Act 1992.
Paul Kenny, acting general secretary of GMB, said: "Asda management needs to take a clear message from this – GMB is not going away and the union will fight on every front to protect our members' rights."
Asda said it was disappointed with the ruling and is considering an appeal.