London Underground relies on the correct time to control all aspects of its operation. There are many systems (some automated, some not) that are affected by the bi-annual clock change. The introduction of Night Tube services means that the impact of clock changes are greater than in the past. Many London Underground systems are designed to change from one day to the next at 03.00 whereas in Standard Time the change from GMT to BST occurs at 01.00. To cater for this throughout the various London Underground systems, the concept of London Underground Railway Time has been introduced and is used within this notice.
Standard Time removes the 01.00 to 02.00 hour (on Saturday night/Sunday morning, 25th/26th March) whereas London Underground Railway Time will remove the 02.00 to 03.00 hour.
Times shown from 01.00 until 01.59.55 are preceded with the letter G to indicate that on the railway we are continuing with GMT. At 03.00 BST the railway will move in common with Standard Time.