Tesco says it is extremely disappointed with its workers' decision to go on strike this week.

The Mandate trade union is mounting the action at 70 shops, in a row over a change to the contracts of 300 staff at the retailer.

In a statement, the company says it has yet to decide on a date to implement the changes, and has offered those affected a voluntary redundancy scheme.

However the union's General Secretary John Douglas says unless Tesco agrees to go to the Labour Court the strike will go ahead: