Originally Posted by Viajero
The rule for a OWE stopover reads:
152N . 1. A STOPOVER IS A BREAK OF JOURNEY OVER 24 HOURS.
My planned flight arrives at LHR at 21:30, and I want to connect with another that departs LHR at 21:30 the following day.
The way I see it that's 24 hours exactly (not over) so it should be allowed as a transit. Will the airlines agree?
I guess that depends on how persuasive you are.

I agree with your interpretation though, and armed with the star file and some gentle brow-beating, you should be able to prevail. I have no direct experience of this myself though.