There are significant cancellations for morning of 20th December, posted around midnight.
As pointed out elsewhere, the iPhone/iPad app seems to work for arrivals and departures, even when the web site is inoperative.
No Swiss Christmas dinner for me today!
Some of the news reports make me pleased not to be going to LHR. One mentioned passengers being allowed off trains, but then barred from entering the terminals. Sounds terrible.
Good luck to all.