A little known and untested law could allow British trade unions to organise mass industrial action on a scale similar to strikes seen in France and Greece.
The UK's trade union movement is holding a rally outside the Houses of Parliament on Tuesday to protest at the government's spending cuts.
TUC general secretary Brendan Barber told supporters in Westminster that they should fight the government's cuts programme, which would make Britain "a more unequal, more squalid and nastier country".
Could this be the precursor to mass strikes in the UK, similar to those seen in Europe?
The trade unions certainly have the will to stage mass industrial action.
At the TUC Conference in September, members backed a motion to "support and co-ordinate campaigning and joint union industrial action, nationally and locally, in opposition to attacks on jobs, pensions, pay or public services".
Despite membership continuing to fall, the movement also has the numbers.
Government figures show there are still 7 million trade union members, and almost two out of three of them are in the public sector, where the cuts will hit hardest.
But there are numerous steps unions have to take before their members are legally protected from sanctions like dismissal.
Recently, unions have struggled with these in single ballots, let alone in coordinated action.
Also key is the principle that there has to be a trade dispute with an employer before a strike can go ahead, so for all the rhetoric, a call to action on political grounds won't suffice.
But the trade unions could have one powerful legal weapon at their disposal.
If you delve deep into the Trade Union Labour Relations Act (1992), which sets out the current law on industrial action, you will find Section 228A, which has yet to be tested.
This allows a single ballot of union members with any number of employers around the country - provided that the union is in dispute with all of them - and it appears that it does not even have to be the same dispute.
Tom Flanagan, employment partner at Pinsent Masons law firm, says that if unions could organise a strike on that provision in the private and public sector, it could mean a series of national strikes which, if organised in concert, could almost amount to a general strike.
"There are two problems with this," explains Mr Flanagan. "There has, in the past, been a lack of joint interest between widely differing workforces, particularly in the private sector.
"It's different in the public sector - there are some common contracts and bargaining agreements which do provide this common interest between large groups like doctors, teachers and civil servants," he said.
"Secondly, logistically, it would be very difficult to organise given all the balloting requirements."
If trade unions can jump these hurdles, questions remain over whether they will get the public support that is critical to pressuring politicians into caving in to their demands.
A recent survey by the Chartered Institute of Personnel and Development found that after the pay freezes and cuts in working hours many have already endured, a majority of workers would quickly lose sympathy if strikes caused disruption to essential services.
So the trade unions do have the theoretical power to cause widespread disruption; it remains to be seen if they have the political savvy and organisational skills to turn their bark into a bite.