I think you mean its weakest point.
I understand BA has seven de-icing rigs at T5. I am not certain if this is enough for seven aircraft simultaneously, or means just seven trucks.
I don’t personally think this is adequate, having been stuck for four hours on board in similar circumstances as others describe here.
But it’s not far short of adequate – if you consider something like 30 take offs per hour total for LHR in bad weather, I would expect BA to be able to de-ice something like 15-20 aircraft per hour. If a 747 takes 30 mins, 7 rigs (assuming a rig is enough for one aircraft) should be able to manage 14 747s per hour; obviously it takes less time to de-ice smaller shorthaul planes, so that seem to be about the right capacity (assuming a reasonable supply of skilled labour to operate the rigs and a good supply of de-icer).
The issue here was nothing whatsoever to do with the other airlines/BA’s capacity to de-ice aircraft, as that was never even permitted due to restrictions moving equipment around the stands..
The airlines are simply not responsible for keeping runways and stands clear.
That is BAA plc’s role, and BAA plainly did not have adequate kit to de-ice runways or to de-ice stands to allow access by the airline’s de-icing rigs.