TORY ministers must make a “clear commitment” not to overturn a reinstated ban on bosses using temporary agency workers to break strikes, the TUC demanded today.

The widely criticised end to the long-standing ban — enacted in the dying days of former prime minister Boris Johnson’s scandal-hit administration last summer — was quashed as of today following a High Court ruling last month. 

Judges found that then business secretary Kwasi Kwarteng failed to consult unions as required by the Employment Agencies Act 1973 when making the draconian changes. 

A TUC-led coalition of 11 unions, represented by Thompsons Solicitors, challenged the attack on workers’ rights, paving the way for it to be struck down.

An embarrassed Downing Street recently ruled out appealing the judgement, but it is yet to confirm its longer-term plans.

Another attempt to reverse the ban, originally put in place in 1976, would be a “huge mistake,” the union body stressed.

TUC general secretary Paul Nowak said: “Ministers know they broke the law when they tried to push through unworkable, shoddy legislation on agency workers covering for strikers.

“That’s why they have done the right thing and decided not to appeal against the High Court’s judgement.

“Bringing in agency staff to deliver important services in place of strikers risks endangering public safety, worsening disputes and poisoning industrial relations.

"It’s time for clear commitments from ministers that they won’t overturn the ban [again].”

The call was backed by the Unite and GMB unions, which are embroiled in several industrial disputes as the biggest strike wave to sweep Britain since the 1980s continues apace.

Unite accused homeless charity St Mungo’s, which has been hit by spring and summer walkouts over plummeting take-home pay, of using a “number of agencies to break the strike” and urged it to adopt a different approach to avoid an “expensive, administrative nightmare.”

General secretary Sharon Graham hailed the fact that “pitting worker against worker in an attempt to union-bust is no longer an avenue hostile employers can use.

“St Mungo’s needs to stop looking for ways to break the strike and start looking for ways to solve it.”

A charity spokesperson told the Morning Star: “We are aware of the change in legislation on using agency staff and we have put in place arrangements which ensure we do not breach this legislation in any way.

“We are doing everything we can to work with Unite so together we can end this dispute.”

And GMB urged Canterbury City Council and the refuse firm it owns — Canenco — to make similar commitments after the union accused councillors of bringing in agency staff to cover refuse workers downing tools last month. 

Union organiser Frank Macklin said: “It’s about time more energy was used to get around the negotiating table rather than using Tory anti-union laws to try to undermine the strike. 

“Yet again we remind Canenco and the council of their legal obligations not to use agency workers to cover striking workers —GMB will not hesitate to refer the matter to the police if they breach this.”

A council spokesperson told the Star: “We’re aware of the legal position.

“Canenco as an employer and a business always follows the letter of the law.”

The TUC also repeated calls for Westminster to scrap the widely condemned Strikes (Minimum Service Levels) Act, which was rushed through Parliament before the summer recess.

The legislation empowers employers and even ministers to fire workers who refuse to cross their own picket lines and provide an as yet undefined minimum service level during walkouts across key sectors. 

The Act will “only sour industrial relations and drag out disputes,” Mr Nowak warned.