Len McCluskey, the General Secreatry of Unite the Union, said on Sunday that he would consider breaking the law to fight the Trade Union Bill.
Speaking at the anti-austerity march in Manchester, McCluskey said that Unite, the largest union in Britain and Ireland, will "stand by our members in struggle," and "if that means taking us outside of the law then so be it."
McCluskey also criticised the Conservative government's handling of public services:
"We're here in order to send a very clear message to this Tory government. If they thought on May the 7th that we were going to disappear, well, think again because we're here to fight for everything that belongs to us, our welfare state, our National Health Service, universal education," he said.
The Conservatives' Trade Union Bill has been criticised for threatening workers' right to strike, requiring support from 40% of eligible voters if attempting to do so.
The leader of Unite told the crowd on Sunday that the march was also about "fighting the attacks on trade unions," and that the new "pernicious" bill would turn unions into "nothing more than advice agencies."
The new laws will cover key public sector workers including nurses, teachers and fire fighters.
Anti-austerity protestors turned out in their thousands on the streets of Manchester to coincide with the Conservative party conference taking place there.
There has been mixed reports of behaviour at the march, as Chief superintendent John O’Hare of Greater Manchester Police said that the majority of people on the march showed “good grace”.
However, journalists reported being spat on as well as a Conservative attendee being egged.
Billy Bragg also attended the event, who had performed at a 'Refugees welcome' rally the day after Jeremy Corbyn was announced as leader of the Labour party.
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