Originally Posted by
flarmip
And for the OP's benefit, the relevant case law (WZ v Austrian) says that the airline is liable for:
The "shortcomings" here being the failure to arrange transport to the booked destination airport.
So the question would be whether the cost of a taxi is "necessary, appropriate and reasonable". At midnight when there are few public transport options? Probably, yes. But during the bulk of the day when public transport will get you there just as quickly if not quicker, with only one change, and at a fraction of the cost? Probably not.
As a data point on this, my OH was re-routed a couple of years back on a LHR-EWR to JFK. The car had been rented from EWR and she took a cab from JFK to EWR at USD200. Public transport was available but she was in no condition to take this on the trains/buses with a large suitcase and carryon. BA paid this cab fare with no questions asked.