Trains home fill up in a fairly predictable order, and being on the platform a few minutes earlier changes the journey considerably. This page tracks the exact time left until 2:05 pm, whether that is the train itself, the walk to the station, or the point work has to stop for either to happen.
Nothing is downloaded, nothing is registered, and nothing is left on the device afterwards. The whole count runs inside the page you already have open. Closing it costs nothing at all, and opening it again later simply shows the accurate gap to 2:05 pm as it stands at that moment.
Between the last Sunday in March and the last Sunday in October the country runs on BST rather than GMT, which is why timetables and confirmations sometimes carry the label as well as the number. This page counts down to 2:05 pm using whatever your device is currently set to, so the switch is handled for you.
Common questions
What happens if 2:05 pm has already gone for today?
The count simply carries on towards the next occurrence, which is tomorrow. That rollover happens on its own — the page does not need reloading and there is nothing to reset by hand.
Which clock does it use?
Your own. It reads the local time and time zone from the device you are looking at, so the figure reflects where you actually are rather than a fixed zone written into the page.
Will this alert me when the time arrives?
No. It is a live number rather than an alarm — nothing rings, buzzes or notifies you at zero. If you need to be interrupted at 2:05 pm, set an alarm as well and treat this page as the running total.
Is it affected by the clocks changing?
Only in the sense that your device is. When the change between GMT and BST happens at the end of March and October, the device adjusts and the countdown follows it without anything to do here.