Simon Calder now reporting on the BA LHR chaos:
British Airways: 50,000 passengers stranded after de-icing meltdown at Heathrow | The Independent
Rough estimates of the numbers affected (c-w-s could no doubt calculate it with much greater precision):
The Independent has calculated 27,000 BA passengers are stranded in London, a further 20,000 stuck in European airports, and another 3,000 at airports elsewhere in the UK and neighbouring countries after their flights to Heathrow were diverted.