Shopworkers’ union Usdaw has put its support behind David Miliband to succeed Gordon Brown as leader of the Labour Party.

Usdaw, which represents 386,000 members at retailers such as Tesco, will ballot the 366,000 who pay the union’s political levy in September.

Usdaw general secretary John Hannett said Miliband was a “long-time friend” of the store staff’s union. “He supports our campaigns against violence, threats and abuse against shopworkers and for the extension of workplace rights to help working parents,” said Hannett.

Miliband said he was “delighted” by Usdaw’s support. He maintained: “Usdaw has always been a leading voice in promoting rights and support for working families. They worked closely with labour in power to deliver tax credits for working parents, extended paid maternity leave, the introduction of paid paternity and much more besides.”