The only surprise about today's news of massive disruption for British Airways passengers is the timing: it's not summer. BA customers are used to the annual lottery of travelling with the airline between June and August, having experienced delays and cancellations three times over the past four years - twice due to wildcat strikes, once in the aftermath of the August 10 terror alert.

The latest upheaval, which would see eight days of strikes over the next three weeks, is rooted in BA's fractious industrial relations record. Around two-thirds of its 46,000 staff belong to a union and its largest bloc of unionised staff - nearly 11,000 cabin crew - are staging a walkout next week.

Flight attendants say senior managers are ramming home the airline's sick leave policy with excessive force, causing some cabin crew to turn up for work while sick. One senior BA employee that I spoke to, who is not part of the cabin crew operations, said stewards bunk the occasional day because the crew rota system is too rigid. This inflexibility plays havoc with social lives, in some cases giving crew the choice of taking a sick day and then having to lie through their teeth when they have a mandatory sickness absence interview with a BA manager, or missing a wedding/stag do/birthday. Also, cabin crew say something as seemingly innocuous as being on antibiotics means you have to down trolleys and withdraw from a flight.

BA says the average sick leave rate of its cabin crew, at 12 days per year, is unacceptable and forces the airline to hire 1,000 more flight attendants than is necessary. Such is the bitterness of the briefing over this issue alone, that a reporter barely gets time to run through the secondary issues in the dispute, such as a yawning disparity in pay rates between flight attendants who joined before 1997 and those who joined afterwards.

If you think this is the equivalent of two bald men fighting over a comb - a dispute over whether you can have a day off if you've got flu? - then you will realise how big a problem Willie Walsh, the BA chief executive, has on his hands. Three quarters of BA cabin crew - not the most militant people you'll ever meet - are willing to strike over what constitutes a valid sick note. Industrial relations at BA are in urgent need of repair and if both sides don't work out the fundamental differences that underscore this dispute, then Heathrow airport might as well put up more marquees outside terminal four and keep them there.