The government may try to stop or delay a planned national strike over pension reform involving millions of public-sector workers by urging employers to mount a court challenge arguing the walkout is unlawful, lawyers said.

Unions representing upwards of 2 million workers are busily balloting members ahead of the one-day stoppage on November 30 in a row over the deficit-cutting coalition government's plan to increase employee pension contributions.

With no sign of a breakthrough lawyers said ministers could push a big public sector employer to seek a court injunction in a last ditch attempt to avert the walkout by showing it to be politically motivated, rather than simply a trade dispute.

Stephen Blunt, a partner at Clyde & Co, said he was certain the move was being discussed behind the scenes by ministers together with one or two of the many thousands of employers to be hit.

I think an employer will come forward and do it, they are just waiting for the right timing - they will say: 'this is not being organised as a legitimate trade dispute, this is being organised as a political dispute against government policy' which is unlawful, he told Reuters.

Some of Britain's biggest unions believe the coordinated action - involving 18 unions -- could come close to numbers seen during the 1926 general strike when an estimated 3 million were involved. Unison alone, the country's second largest union, is balloting a record 1.1 million workers.

Lawyers said it was that level of perceived organisation across sectors - teachers, civil servants, health workers to dustmen and grave diggers are pledging action - which could trigger a full judicial review into the reasons for the strike.

The injunction could be served against one union, like Unison, one of the largest, or it could be against all of them, said Blunt, adding that a challenge was more likely to come if more stoppages were called -- something unions have threatened.


Blunt said the basis of a court challenge would revolve around the language used by union chiefs at public meetings when they are bashing the lectern and talking about taking the government on. Recent combative language on fighting public sector cuts and job losses were a good example, he said.

With the economy faltering, unemployment rising and inflation twice target, unions have broadened their attack on the government to include its deficit reduction strategy as a whole which they say is harming growth and public services.

David Bradley, head of employment law at DLA Piper said a court challenge was entirely plausible and would be an extremely interesting case to run.

Looking at the rhetoric there has been on this, if someone wanted to have a test, then it's probably as good a grounds for one as any, Bradley told Reuters.

Kathleen Healy, a partner in employment law at Freshfields Bruckhaus Deringer also said it was an option but called it a pretty dangerous test (case)to run.

Because although you could say the general thrust of the strike has a political motive, there are underlying issues in the industries concerned that definitely do fall within the trade dispute. I think it would be a brave court to say that this is entirely political, Healy said.

A Conservative lawmaker said legal action could be used at a later stage in the dispute.

If there was credible legal advice from a senior solicitor saying that was possible I would be happy to call for it, he said on condition of anonymity.

It's quite an aggressive thing for the government to do and I think they will wait to respond to the ballot results ... I think if they were ever going to contemplate legal tactics they would come late.

Blunt said even a test of the labour laws may be sufficient for ministers because an injunction once granted would mean a strike could not begin until a full hearing had run its course.

He said there was precedent in the private sector for judges to grant injunctions, for instance in the recent high-profile dispute between British Airways and its cabin crew staff.

So as a delaying tactic, it could also work, he said, explaining that due to Britain's strict labour laws unions had little over a month to carry out industrial action once a strike date was formally announced before having to re-ballot all its members, a costly, complex and labour-intensive process.

Brian Strutton, national secretary for the GMB, the country's third largest union that has just begun balloting said he was not too worried about legal challenges because unions had poured over the possible legal pitfalls for months.

We have an absolutely bona fide trade dispute within the meaning of the legislation relating to the pensions. No one can stop anyone testing it, but that will fail. This a trade dispute

pure and simple, he said.

Asked for reaction on the possibility of a legal challenge the government's Cabinet Office said in a statement: We don't comment on hypothetical situations.

It said it was continuing to engage with the Trades Union Congress (TUC) - an umbrella group representing the unions in the pensions row - and urged it to respond constructively.

The TUC characterised any possible court challenge as sabre rattling saying the dispute should be settled through negotiation, not diverted into the courts.

But it takes two to negotiate, and the government needs to show that it wants to engage in serious talks rather than endlessly restating its position, a spokesman said.

(Editing by Maria Golovnina)