1st class mail uk until witch hour next day

A fascinating question!

In the UK, the Royal Mail's standard delivery times for 1st Class mail are:

However, there is no such thing as a "witch hour" in the Royal Mail's delivery schedule. The concept of a "witch hour" is more of a mythological or fictional idea, often associated with folklore and superstition.

If you're looking for a specific delivery time for your 1st Class mail, I'd recommend using the Royal Mail's online tracking service or contacting their customer service team for more information. They can provide you with a more accurate estimate of when your mail will be delivered.