The three-day London Underground strike should not affect holidaymakers, says BAA.
The authority has said the tube strike that began last night is unlikely to severely affect travellers departing from London airports, despite early reports of disruption.
More than 2,300 tube maintenance workers walked out for 72 hours from 6pm yesterday.
The strike has brought three quarters of the London Underground network to a halt. At Victoria station metal gates blocked the entrance to the Tube, and posters informed passengers that the Victoria, District and Circle Lines were closed.
Services on the Piccadilly Line to Heathrow will be operating as normal, although they are likely to be very busy. The Heathrow Express, Gatwick Express and mainline trains to Luton Airport will also be unaffected.
A second 72-hour strike is scheduled for September 10.