Union says plans would make legal strikes 'close to impossible'
Prime Minister David Cameron, who last week described a 24-hour stoppage on the London Underground rail network as "unacceptable and unjustified," promised the curbs as part of his re-election campaign earlier this year.
Having won a surprise majority at May's election, Cameron is likely to gather enough parliamentary backing to turn the proposals into law largely on the lines he wants.
The new measures will require a turnout of at least 50 per cent in ballots for industrial action, and in key sectors such as health, transport and education, strikes will also need the backing of at least 40 per cent of those eligible to vote.
Currently there is no minimum threshold for turnout, with ballots only requiring a simple majority to back action.
"People have the right to expect that services on which they and their families rely are not going to be disrupted at short notice by strikes that have the support of only a small proportion of union members," employment minister Nick Boles said in a statement.
The plans also include a four-month time limit for taking industrial action after a ballot and requiring union members to make an active choice to pay into political funds. One union warned that would bankrupt the opposition Labour Party, because unions are its biggest financial backers.
While business lobby groups welcomed the measures as better balancing the rights of workers with those of people who rely on their services, the Trades Union Congress has said the plans would make legal strikes "close to impossible."
The trade union movement was significantly weakened under Cameron's Conservative predecessor Margaret Thatcher, whose 1985 defeat of the miners' union after a bitter year-long strike was considered a defining moment of her premiership.
"It is part of a campaign of demonisation of trade unions," he told reporters at a parliamentary lunch on Tuesday. "It is designed to cause problems for the Labour Party and the trade union movement."