The Conservative Government will today publish plans for new laws designed to crackdown on strikes and picket lines.

Ministers want a minimum turnout of 50 per cent in a strike ballot before a walkout is legal.

Workers in some vital public services will also face an additional hurdle before they can begin industrial action.

Union leaders denounced the plans as "draconian" and said would remove all incentives for employers to listen to staff.

The Tory government says that at the moment a small minority of trade union members can fundamentally disrupt the lives of millions.

The new Trade Union Bill will address that imbalance, they say.

Under the plans, strikes will have to be held within four months of a ballot and there will be greater controls over the time that union reps are allowed to spend on activities in the public sector.

A consultation will also be launched on modernising picketing rules.

Unions said they would also be forced to give 14 days notice for strike action, while a ban on agency staff would be lifted.

Ministers also want to change trade union subscriptions so members have to actively choose to pay into funds for political parties.

Labour has claimed that that move is designed to cuts off millions of pounds in legitimate donations.

Last night Scottish ministers said that they opposed the measures to "further restrict the right to strike".

Business Secretary Sajid Javid said: "Trade unions have a constructive role to play in representing their members' interests but (we have to) balance their rights 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.

Employment minister Nick Boles added that people had 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."

Business leaders welcomed the announcement.

But Trade Unions warned that if adopted the proposals would damage industrial relations and bankrupt the Labour party.

Paul Kenny, General Secretary of the GMB union, said "The Bill removes all incentives for employers to heed their own workers and settle disputes.

"When workers jump through the draconian hurdles required for their vote for strike action to be lawful employers can ignore the will of their own workers.

"Workers will have to give an employer 14 days notice of strike action. This is more than enough time for employers to legally hire another workforce to break the strike.

"This blatant one sided approach is guaranteed to poison the relationship between workers and their managers. It will lead to even more trouble."

UNISON General Secretary Dave Prentis accused ministers of not being "on the side of working people"

"These spiteful proposals will deny millions of ordinary workers a voice at work. Strikes are rare and the decision to lose a day's pay is never an easy one - especially for public sector workers who have suffered many years of pay restraint.

"When unions win a pay rise or safer working conditions for their members everyone in the workplace gets to benefit.

"Democracy won't be enhanced by vindictively raising thresholds but by modernising balloting and allowing workers to vote from their phones and tablets."

TUC General Secretary Frances O'Grady described the Bill as "an unnecessary attack on workers' rights and civil liberties".

She added: "Getting a pay rise or defending terms and conditions will become far harder for working people... Making it a criminal offence for seven people to be on a picket line is a waste of police time and not something you would expect in a country with a proud tradition of liberty."

An Scottish Government spokesman said the Bill aimed to bring in "highly regressive reforms, making it more difficult for employees to have their voice heard".

"We believe that trade unions are key social partners, playing an important role in sustaining effective democracy in society, particularly at the workplace, and that the existence of the good employment practices they promote are a key contributor to economic competitiveness and social justice. "Attacks on the rights of our workforce will be bad for individuals, bad for our economy, and bad for democracy in this country."