On June 1st, only one BA flight took off between 1pm and 3pm at Heathrow
Someone should suggest BASSA/Unite take a look at
Casper flight movement display and set the date/time to 1 June at 1pm in replay mode and just sit back and watch all the BA planes that took off! Over 20 airborne between 1 and 3 by my reckoning. Perhaps the switch from Westerlies to Easterlies confused them.