Momentum seems to be building behind David Miliband's campaign to be Labour leader after a second trade union put its support behind him, making him the only candidate so far to have secured union support.

Mr Miliband has been backed by Community Union, which traditionally has strong links to the steel and textile industries. It is the second of the 14 trade unions affiliated to the Labour Party to declare who it will be supporting in the current leadership contest.

Two weeks ago Mr Miliband also secured the support of the Union of Shop, Distributive and Allied Workers (USDAW). So far no other unions have thrown their support behind any of the five candidates.

Michael J. Leahy OBE, General Secretary of Community Union, said, "Over the past 13 years Community Union worked with the Labour government when we could and against the Labour government when we had to. So I recognise that the leadership of the Labour party is not an empty title, but a position that can make a very real difference to the lives of our members. While I accept that all the candidates are worthy and capable, it is my belief that of all the candidates, David Miliband, has the gravitas, the dignity and the commitment to the issues that will make him a successful leader.

Mr Miliband, commented, "I am honoured and delighted to have secured the support of Community Union and look forward to making my case to the union's members whether they are rolling steel in South Wales, stitching together shoes in the midlands or working behind the counter of a high street betting shop.

"Community Union is the model for new unionism, with their focus on supporting members at home and in their local communities as well as the workplace. Community Union is showing how to change an organisation into a movement and this echoes what I believe the Labour party must do also."

Mr Miliband, together with his brother Ed Miliband, have so far secured the most supporting nominations from Labour MEPs, Constituency Labour Parties and now Trade Unions.

Rival and arch-Brownite Ed Balls has received surprisingly little support as of yet from the broader Labour Party and its affiliates. Mr Balls was expected to get significant backing from trade unions but so far has only been supported by one Constituency Labour Party (his own) in addition to the 33 nominations from MPs needed to get him on the ballot.

So far candidates have the following support from Members of Parliament (MPs), Constituency Labour Parties (CLPs), Members of the European Parliament (MEPs), Trade Unions (TUs) and Socialist Societies (SSs):

Diane Abbott

MPs: 33

CLPs: 4

MEPs: 0

TUs: 0

SSs: 0

Ed Balls

MPs: 33

CLPs: 1

MEPs: 0

TUs: 0

SSs: 0

Andy Burnham

MPs: 33

CLPs: 8

MEPs: 1

TUs: 0

SSs: 0

David Miliband

MPs: 81

CLPs: 22

MEPs: 4

TUs: 2

SSs: 0

Ed Miliband

MPs: 63

CLPs: 28

MEPs: 5

TUs: 0

SSs: 0

Yet to declare

MPs: 0

CLPs: 572

MEPs: 3

TUs: 12

SSs: 15