There are bound to be some delays tomorrow since people and aircraft aren't where they ought to be. Some flights had very long delays indeed. Plus there are one or two weather events out there. For the record here is BA's 16:30 hrs statement:
We have resolved the temporary systems issue from this morning which affected a number of our flights today. We apologise to all our customers caught up in the disruption, and appreciate how frustrating their experience has been.
Our teams have been working tirelessly to get the vast majority of customers on their way, with most of our flights departing. Our flights are returning to normal, however there may be some knock-on operational disruption as a result of the issue earlier today. We continue to advise customers to check ba.com for the latest flight information before coming to the airport.
Cancellations for 8 August (Thursday)
BA776 ARN 07:05
BA938 DUS 10:45
BA215 BOS 18:25 (this I noticed earlier today, it may be unrelated to the current problems)
and more relevant perhaps for the forum, the Inverness night stop got scrubbed so there isn't an early morning return to London.