A shortage of available train crew means some Elizabeth line services between London Paddington and Heathrow Airport will be cancelled or revised.
Disruption is expected until 05:30.
Customer advice:
You can use your ticket on London Buses via any reasonable route at no extra cost.
Check before you travel:
You can check your journey using the National Rail Enquiries real-time Journey Planner.
Compensation:
You may be entitled to compensation if you experience a delay in completing your journey today. Please keep your train ticket and make a note of your journey, as both will be required to support any claim.