Britain's biggest union yesterday threatened co-ordinated strikes by public service workers and issued a warning shot to Labour MPs that funding could be cut if they did not support its policies.

Unison pulled back from slashing financial support to Labour by rejecting a move that would have cost the party hundreds of thousands of pounds to fight elections. But general secretary Dave Prentis said there would be changes to the way Unison gave financial support to Labour MPs, currently in the form of a grant of about £1,500 a year to their constituencies.

The funding will come under far more scrutiny, especially if MPs were against Unison's policies, which included opposition to foundation hospitals and the controversial private finance initiative