If you are arriving into the U.K. after 24 Oct, and are “fully vaccinated” as defined under the U.K. rules, then I would *not* waste money on a Day 2 booking test just yet.

There is a detailed government announcement due today (to follow the tweet last night), scrapping the PCR test requirement for such passengers, and supposedly replacing it with a much cheaper lateral flow test requirement.

And as mentioned above, you may not even need that for a transit, but those rules may also be simultaneously changing, so I’d wait a day or two before booking any tests.