The Communication Workers Union (CWU) is in the High Court as Royal Mail management tries desperately to stop a 48-hour strike, starting at 11am on 19 October.
If they are granted an injunction, the whole labour and trade union movement must come to the aid of the CWU, which will be fighting for trade union rights and the basic right to strike as much as the industrial issues in their 'four pillars' campaign.
The message will be sent to all unions that it's not enough to overcome the undemocratic voting thresholds in the Tory Trade Union Act if companies can get the judges to stop action.
The CWU has waged a tremendous mass campaign of mobilising members over the last few months, resulting in an incredible vote for strike action with a majority of nearly 90% on a turnout of 73%.
Management are trying to claim that the union hasn't fully exhausted the external mediation process before taking industrial action, yet it is they who have rode through 18 months of negotiations and now intend to break the promises made at the time of privatisation, in particular by closing the final salary pension scheme.
The bosses can break agreements but the union and their members have to comply with what they rightly consider a non-mandatory procedure.
It's clear that this is a stalling exercise in which Royal Mail hopes to force a re-ballot or other delays to avoid the peak time of the run-up to Christmas.
Actually, it is sign of weakness of the bosses, who have been terrified by the strength of feeling reflected in the vote and the euphoria of postal workers at the result.
There is a real feeling that this dispute is an opportunity to push the company back at a time when the Tory privatisers are in crisis and Jeremy Corbyn has popularised the idea of renationalising Royal Mail and other privatised sectors such as rail transport.
This militant mood has seen a whole series of unofficial wildcat action at Royal Mail offices over the last few months, which is part of the tradition of postal workers.
The prospect of further walkouts if the official strike is ruled out will weigh on the minds of the judges and also the Tories.
Such a blatant judgement could expose the strike-breaking reality of the Trade Union Act and actually legitimise unofficial action at a time of huge anger in both the public and private sectors on pay.
The best way to ensure that the CWU isn't isolated is for the TUC and the unions to organise practical support and be prepared to call mass solidarity demonstrations and even strikes.