Ah, right! Here's an approximate comparison then, measuring from one of the terminus stations serving central London, according to railway timetable data:
0h 30m - Heathrow
1h 00m - Gatwick
1h 00m - Luton
1h 30m - Stansted
2h 30m - Manchester
3h 00m - Birmingham
3h 00m - Bristol
4h 00m - Cardiff
Plus Channel Tunnel trains:
2h 00m - Brussels
4h 00m - Amsterdam
Looks like I was wrong about Manchester being further than Cardiff though!!
It's very reasonable, and I wouldn't hesitate to do this if it was a business trip.
Many flights have been diverted to Manchester, partly because airlines with flights to Heathrow also have flights from Manchester, but are less likely to have flights from the other London airports.
Manchester Airport railway station is 2 minutes walk from the airport's main entrance, I think using a covered walkway, or maybe it was underground. Going to London takes 2¾ hours with one change, trains run every 20 minutes.
It would be more convenient to be diverted somewhere a bit closer, but on the scale of an intercontinental flight it's not a big deal.
> Cardiff, Birmingham and Bristol as alternatives ... even Amsterdam Schiphol or Brussels would make for a faster journey than Manchester!
Cardiff Airport to London takes 3 hours by train, Bristol Airport about 2½ hours, both are less frequent. Amsterdam is four hours by train, Brussels is around 3 hours.
Birmingham (BHX) and East Midlands (EMA) are the only airports closer to London in travel time than Manchester.
