Originally Posted by Vgravity

In terms of defining the 10 days before arrival - is that 10 x 24 hour periods, or 10 days starting from the midnight after you arrive?

So if I arrive in the UK tomorrow evening from an amber country, then leave the UK almost immediately to a green list country, am I out of the woods the following Sunday evening (ten days later) or Monday (10 full days passing in between with part days not counting)?