I think this requires a little perspective and whilst I would not wish to blindly defend BA I would like to make a contribution that is supportive of them.
Firstly this is the worst winter since 1963.
BA operate at the most congested hub in the world. A hub that has two runways which are planned at full capacity every day. This capacity allows for 48 to 52 landings per hour and this is what the airfield is scheduled to handle. In addition these runways have some of the worst ATC/Noise and other restrictions of any airport in Europe. As a result, when there is any deterioration in weather, be it snow, fog, heavy rain, thunder or even strong en route winds, the number of aircraft that can land is reduced. This happens on around 60% of all days in a year ranging from 0 per hour to the full capacity.
When capacity restrictions are put in place it is the BA that suffers disproportionately due to LHR being their main hub. When the capacity is such that short haul flights get delayed significantly, BA must look to, firstly, changing aircraft (limited by type and crew availability and also by stand congestion.) and then cancellations. These, when planned are based on revenue with the highest revenue routes being protected.
They have spare (standby) aircraft, flight crew or cabin lying around but these are quickly used to protect services
Their home in T5 whilst being state of the art is not yet finished because the airport authority have failed to deliver the infrastructure. The BAA built T5 with a train service that does not allow security cleared passengers to move from T5B to T5A and this situation will not improve when T5C opens. The effect of this is to make gate/stand planning more complex and when fact is added to the ATC and runway restrictions it makes BA operation significantly more difficult to manage.
There may not have been precipitation in the LHR area however de icing has been ongoing almost non stop since Dec 17th. BA de ice all short haul services ready for the first departures over night and this helps. De icing delays flights as it can only be done prior to push back as the BAA have always refused to allow a central de icing point on the airfield ( similar to Munich). As a result all passengers need to be on board and all holds and doors closed prior to de icing.
There is no benefit to BA cancelling flights and it is done as a last resort and to protect the rest of the operation. Some flights may have been cancelled as their staff could not get to airports as a result of the bad weather and lack of gritting on minor roads. A week after the snow I am still struggling with over 8 inches of slush and ice and I live within 40 minutes of Heathrow.
None of the above means that you would not be entitled to some compensation but the fact that other operators keep flying is due more to their limited operations than BA incompetence. Nor does any of this make the experience any less painful or upsetting.
I would pose one question however, who does benefit from this disruption?
I would suggest the answer is the BAA, their shop’s, their car parks and restaurants’ make a killing between bored passengers and generous airlines that provide refreshment vouchers. Perhaps if they had to compensate passengers for delays then they might provide a better airport experience.