It will become tougher for British workers, including employees of Indian companies in the UK, to embark on industrial action, as the Conservative government announced plans to revise the rules.

It is widely considered the largest overhaul of rules governing trade unions since the days of the Margaret Thatcher government in the 1980s.

The Trade Union Bill, announced by Business Minister Sajid Javid on Wednesday, will require a turnout of at least 50 per cent for a ballot seeking to sanction industrial action to be valid.

While in the past industrial action, once sanctioned by a ballot, could continue indefinitely, mandates will only last for four months, with unions being required to go back to their members for further approval if they wished industrial action to continue beyond this period.

The Bill will also require unions to give in the ballot paper a clear description of the kind of action they hope to take, unlike in the past where the exact nature of the action could be determined after the ballot had taken place.

The government has also launched a consultation on removing the ban on the use of agency workers during a strike, a particularly controversial change.

Javid said the changes would balance the rights of unions with those of “working people and business.” “These changes are being introduced so that strikes only happen when a clear majority of those entitled to vote have done so and all other possibilities have been explored.”

The government will also consult on requiring at least 40 per cent of all ballotable members to sanction strike action in key sectors such as health, education, transport, fire and energy sectors.

And in a move potentially very damaging to the Labour Party, it will require all union members to have to opt in (rather than the current situation in which they have to opt out) from paying into political funds, set up by trade unions, which is a key source of funding for the party.