If Gordon Brown succeeds Tony Blair he must change policies to avoid defeat at the next general election, the joint leader of a new super-union says.
Tony Woodley is concerned about the result of the next election
Tony Woodley was speaking to the BBC weeks before the formal merger of his union, the Transport and General Workers' Union, with Amicus.
The general secretary said he was worried the chancellor would become a "Blair mark two" as prime minister.
This could result in defeat at the polls, he said.
Unions are angry that the government recently opposed better employment protection laws for temporary and agency workers and the fact that Mr Brown backed below-inflation public sector pay settlements.
Negotiations are already taking place on those issues with government departments.
Mr Woodley told the BBC he also condemned what he called the casualisation of Britain's workforce not seen since the dockers.
The new super-union will create the UK's biggest union of some 2 million people.
Amicus has 1.2 million members and the T&G has 800,000.
The new union plans to spend £15m on a major recruitment drive.