Len McCluskey has threatened to break the law over the government’s failure to scrap the public sector pay cap for all workers, claiming that anyone who is prepared to do so would be following in the footsteps of Nelson Mandela, Mahatma Gandhi and the suffragettes.

After Jeremy Corbyn and a succession of union leaders criticised an offer from ministers to increase pay only for police and prison officers, the leader of Britain’s biggest union, Unite, said unions must be prepared to back their members in the face of wrong laws.

McCluskey, whose union is Labour’s most generous donor, said he was ready to defy legal requirements in pursuit of a fair pay rise for public sector workers.

“In terms of the concept of a coordinated public service workers’ action, yes I think that’s very likely and very much on the cards. If the government has pushed us outside the law, they will have to stand the consequences,” he said.

Following the introduction of trade union legislation which requires a 50% ballot turnout, the need to always act inside the law has been removed from the union’s rule book, he said.

McCluskey said he and other union members might be willing to go to jail and could follow other historic figures by standing by their principles. “The reality is that the law is wrong and it has to be resisted. I dare say if you’d have been interviewing Nelson Mandela or Mahatma Gandhi or the suffragettes you’d be telling them that they were breaking the law.”

It follows a cabinet agreement on Tuesday that police would receive a 2% pay rise for 2017-18 – half of which is a one-off “non-consolidated” bonus – and prison officers an average 1.7% rise. But the increases offered by ministers will still be lower than the rate of inflation, which at 2.9% has risen faster than economists expected – meaning the offer is a real-terms reduction.

The Prison Officers’ Association has rejected the offer and is planning to coordinate an indicative ballot of members alongside the Public and Commercial Services Union (PCS) to see if members will support a strike.

The pay announcement is unlikely to quell discontent in many parts of the public sector, including the NHS, with the Royal College of Nursing threatening strike action and the University and College Union (UCU) consulting their lecturer members over pay.

Many public sector unions backed a motion put before the Trades Union Congress (TUC) conference on Monday for a 5% increase for all public sector staff, which would cost the Treasury £9bn.

Mark Serwotka, the leader of the PCS, said the government offer was a “pile of crap” and said he might be prepared to break the law under certain circumstances. “The law is wrong, but our union’s response really does depend on the response we get from our own indicative ballot for industrial action from our members,” he said.

The UCU also plans to consult its members over possible industrial action. At least 12 unions have condemned the pay offer but most have taken a more cautious position than McCluskey and Serwotka.

Frances O’Grady, the TUC general secretary, said coordinated industrial action would be a last resort.

The GMB said the extra money for prison officers and police will come from existing departmental budgets – rather than new central government funding – meaning public services will be hit harder.

The TUC general secretary, Frances O’Grady, said a strike would be a last resort. Photograph: Andrew Matthews/PA

Rehana Azam, the GMB national secretary for public services, said: “The idea that we have to choose between decent pay for public sector workers and properly funded services is a false choice.”

The Unison general secretary, Dave Prentis, said it was “a tiny step” in the right direction but not enough. “There must be no selective lifting of the cap. No one part of the public sector is any more deserving than the rest,” he said.

Major unions passed a motion at congress on Monday calling for joint action against the 1% public sector pay cap. The composite motion called for “immediate steps to develop a coordinated strategy of opposition to the pay cap … including … pay demands, campaign activities, tactics, ballots and industrial action”.

Privately, some senior union figures accused McCluskey and Serwotka of “grandstanding”, and claim neither would break the law and would struggle to get enough support for a strike.

“They are both looking for cheap headlines. This will be hammered out with the government in the usual way,” one said.

Senior Labour figures are steering clear of offering their support for illegality in pursuit of improved pay and conditions.

The shadow justice secretary, Richard Burgon, refused four times to say whether he would back illegal strike action. “We support trade unions and the campaigns of people to get the public sector pay cap scrapped. It’s for the trade unions to decide what actions they take,” he told BBC Radio 4’s Today programme.

“In relation to the question of turnouts in strike ballots, what we have always been supportive of is encouraging as many people to vote as possible. What a Labour government would do would be to repeal the Trade Union Act which is seeking to stop trade unions from taking action to stop ordinary people ... from suffering a 14% pay cut in real terms,” he said.

The Liberal Democrat leader, Vince Cable, called for the cap to be lifted across the board. He added: “Nurses, teachers and other public sector workers are set to be hundreds of pounds worse off in real terms as a result of rising inflation. Unless urgent action is taken, the recruitment crisis in nursing and teaching will only get worse.”











