The general secretary of the Rail, Maritime and Transport union will tell a rally of activists that political representation of workers stands at a crossroads in the wake of the decision of the GMB to slash its affiliation funds to Labour by more than £1 million. Mr Crow will tell a rally ahead of the TUC Congress in Bournemouth that it is time for an alternative "party of labour".
Speaking ahead of the event, he said: "Over the past two months, we have seen Ed Miliband dancing to the tune of Tony Blair and the rest of the New Labour conspirators as he seeks to hack away at the last remaining shreds of influence held by those who created the party that he leads, the trade unions.
"RMT's message is simple. If others want to stick around and be insulted by those whose only interest is our money and not our ideas then that's a matter for them. For the rest, there is a whole world of opportunity outside the constraints of the Labour Party and RMT would urge them to embrace it."