The large bunch of intercontinental flights all now landing at Heathrow launched up to 12 hours ago, which means a decision to launch them in this coordinated fashion must have been taken 18-24 hours ago. It is clear that BA must have decided then that this was all BS and decided to present the UK govt with a fait accompli. At 19-20.00Z tonight they were faced with 20+ BA flights on the doorstep and had to make a rapid decision on what they were going to do.
Big balls for Mr Walsh, that's for sure.
I sympathise with both views. The risk probably is negligible per flight, but it only takes one double engine failure due to a locally dense ash concentration on one of 30,000 daily flights for everyone to howl for heads to roll.