Underground
The cheapest way to get into London is by London Underground, which has Piccadilly line stations at terminals 1, 2 and 3. You'll never wait more than 10 minutes for a train and it takes around an hour to get into central London, but it may take longer if you are travelling to destinations not on the Piccadilly line.
A single adult journey to zone 1 costs £4, but the cheapest way to use the London Underground system is with an Oyster Card, or a London Travelcard, which you can buy online (www.visitbritaindirect.com/en-GB/SearchResult.aspx?CategoryID=2), or at the underground stations at Heathrow.
The first train leaves Heathrow at 05:13 (05:57 on Sundays) and the last train at 23:49 (23:30 on Sundays). The first train from central London arrives at Heathrow at 06:32 (07:51 on Sundays) and the last train leaves Piccadilly Circus at 00:32 (23:38 on Sundays) arriving at Heathrow at 01:18 (00:25 on Sundays). The underground is generally reliable, but delays do occur and it is advisable that you leave plenty of time to reach your destination.
For more information, see Heathrow by tube, or call +44 (0)20 7222 1234.