Employment agencies have been warned not to help Asda break a proposed strike by Asda distribution workers due later this week.

Last week, staff at Asda's 20 distribution centres across the UK voted for a five-day strike in a long-running dispute over working conditions and union recognition. The strike is due to run from 00.01am on 30 June to 23.59pm on 4 July.

However, the Recruitment and Employment Confederation has sent a letter to its 8,000 corporate members reminding them that it is against the law to replace a striking workforce “either directly or indirectly”.