The GMB has suspended its general secretary, Kevin Curran, in a dispute over allegations of ballot rigging.

Curran, who is seen as a moderniser and has support from Tony Blair and Gordon Brown, was elected with a large majority in a postal ballot supervised by the Electoral Reform Society.

But the union recently launched an official inquiry into claims of ballot rigging during the election and appointed John Hand QC to head the investigation.

Curran denies any involvement in ballot rigging.

He had been accused of contacting Hand about the running of the inquiry, but insisted that he was simply carrying out the union's instructions.

The union's executive demanded an apology, but Curran refused and was suspended on full pay until the investigation is complete.

A friend of Curran said yesterday: "A powerful cabal of some regional barons in the GMB see him as a threat to their vested interests and have cobbled together a trumped-up charge to scupper his proposals to reform the union."