WORKERS should be ready to "break bad laws" if the Conservatives win the election and try to enact anti-union legislation, Scotland's most senior trade union leader said yesterday.

STUC General Secretary Grahame Smith told Edinburgh's annual May Day rally the trade union movement only existed because people "resisted and broke bad laws" in the past and if that was needed again to stop Tory anti-union plans "then so be it".

Another union speaker, Cat Boyd, urged direct action such as demonstrations and occupations if the Tories stayed in power to make the country "ungovernable".

Addressing around 150 people at the Pleasance Theatre, Smith said the Tories were planning "an outright attack" on trade unions and workers' rights, and would allow "scab labour to strike break" and "effectively outlaw" industrial action.

The Tories are planning new thresholds for industrial action, so that 40% of all workers must vote for a strike for it to be legal, rather a simple majority of the turnout.

Smith said: "If the Tory anti-union proposals come to pass they will be resisted. Trade union leaders, even if they talk about the prospect of breaking bad laws, are condemned by the right-wing press. I have no concern at all about being condemned by the right-wing press.

"We would not be standing here today if it wasn't for our predecessors who resisted and broke bad laws, and if that's what it takes to ensure that we can continue to effectively represent our members and our class, then so be it."

Smith also called David Cameron "a liar" and said the Tories were "the party of privilege and patronage, the party of the rich for the rich, the party of prejudice and intolerance - and hopefully on the 8th of May the party of opposition".

He described Ukip as "a pathetic and despicable assortment of oddballs and bigots" and said its leader, Nigel Farage, was "nothing more than a narrow-minded racist".

Boyd, a union activist with the People's Assembly Against Austerity and Radical Independence Campaign, told the audience: "Let me be absolutely clear. If the Tories try to form a government we must be ready and willing to do everything we can.

"We must be willing to break bad laws that were put there to protect the interests of the rich and powerful, to make this country ungovernable."

She told the Sunday Herald later that if Ed Miliband allowed the Tories to stay in power rather than work with the SNP it would be "disgraceful".

She said: "If he allows that to happen, the trade union movement, anti-austerity campaigns, have to be prepared to take direct action, to break the law.

"We need industrial action, we need occupations, we need huge demonstrations that will expose the cracks in that system. It's absolutely incredible that they think they can get away with denying the democratic will of the people."

May Day rallies also took place in Aberdeen, Dundee and Irvine yesterday.

A march and rally in support of international workers takes place in Glasgow today.

Tory MSP Alex Johnstone said: "These measures are being proposed to protect the public and ensure key industries cannot be brought to their knees.

"To suggest the remedy to this is lawbreaking is crazy and utterly unacceptable.

"People like this in positions of power should not be rabble rousing in this fashion."