Passengers looking to get to or from Heathrow airport by rail on December 26, should be prepared for disruption to their travel.
Tube drivers' union ASLEF has announced a series of strike days, with the first due to take place on Boxing Day.
This action coincides with planned Crossrail improvement works by Network Rail, which means that there will also be no services to the airport on the Heathrow Express or Heathrow Connect on December 26.
A statement on the Heathrow Express website said: "Due to essential Crossrail improvement works, Heathrow Express will not be running any services between London Paddington and Heathrow Airport on December 25 and 26.
"Our inter terminal transfer service between Heathrow Terminal 4 and Terminals 1 & 3 will continue to run in line with the planned timetable.We apologise for any inconvenience this may cause."
Passengers are advised to check the latest situation with the planned strike action ahead of travel, and should leave extra time to reach their destination.
The Transport for London website states that on December 26: "A Sunday service will operate on all routes from about 0830 with the following exceptions: On routes 105,111,140, 203, 285, 490, H25, H26 and U3, a Sunday service will operate from about 05.30, in order to serve Heathrow Airport. Route 84 will only operate between New Barnet and Potters Bar stations. Route 477 will not operate".
heathrowexpress.com
tfl.gov.uk