Unite the union has won an appeal against a High Court injunction that put a stop to a series of planned five day strikes by British Airways cabin crew.
The injunction was originally granted to BA after the airline raised concerns that Unite had not reported the results of the strike ballot to its members in the proper way.
Today however a panel of judges, including the Lord Chief Justice ruled 2-1 in favour of overturning the injunction.
Derek Simpson, joint leader of Unite, said, "This is not a moment for being triumphant. We shouldn't have been in this process.
"The case brought by BA was trivial and, in my opinion, irresponsible."
The ruling means that yet more strikes are set to begin on Monday unless an agreement can be found.
The news will not be welcomed by BA, which is still fighting for its commercial future. Last year BA made a net loss of £401 million thanks to what CEO Willie Walsh called "the worst recession the airline industry has known".
Tomorrow BA is to announce a full year underlying loss of around £250 million. The airline will not have been helped by strikes nor by the ash cloud which has recently restricted flights over Europe.