Shopworkers' union backs David Miliband

David Miliband received an early boost in the battle for the Labour Party leadership as he secured the backing of one of Britain's biggest trade unions yesterday.

The Union of Shop, Distributive and Allied Workers (Usdaw), which has 386,000 members, became the first union to endorse one of the five candidates for the leadership. It said it was supporting the former foreign secretary partly because of his willingness to speak up for Labour's record under Tony Blair and Gordon Brown. Union leaders no longer cast block votes in Labour leadership elections but their recommendations to their members, who are balloted individually, can prove influential.

Mr Miliband appears to be the early pace-setter in the contest but many Labour MPs believe he could be overtaken by his brother, Ed, the former energy and climate change secretary, who has distanced himself from key decisions taken by the party when it was in power.

However, John Hannett, the Usdaw general secretary, said its executive council was impressed by the fact "David emphasises the positive progress made during Labour's 13 years in office".

He added: "Our members have benefited greatly from measures like the national minimum wage, tax credits to help make work pay and, of course, the massive improvements to our health and education services."

The candidates face a gruelling round of hustings meetings this summer, with the result declared on the eve of the Labour conference in Manchester on 25 September.

Ed Balls, the former secretary of state for schools, is mounting the strongest challenge to the Miliband brothers. The other candidates are Andy Burnham, the former health secretary, and the left-winger Diane Abbott.