By this stage the kettle has usually been on once already and the radio is halfway through the morning news, which is precisely when nobody is watching the clock. A live count to 8:45 am does that watching for you, updating continuously so the number in front of you is always the current one.
There is one number to read and nothing to choose: hours, minutes and seconds counting down together towards 8:45 am. No start button, no options, no settings page to get right beforehand — just the current gap to that time, updating on its own for as long as you need it.
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 8:45 am using whatever your device is currently set to, so the switch is handled for you.
Common questions
What happens if 8:45 am 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 8:45 am, 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.