If you get a night like tonight then you might get a little extra drinking time.
It all started with the 15:55 ex Moor Street departing 21 late. The Bicester North and Wycombe stops were withdrawn in an attempt to regain time - it didn't. Rolled into Marylebone about 30 down (nearly 10 minutes after the 18:07 Kiddy should have departed - which is the return working). This knocked on to the 18:13 Banbury loco-hauled, the train manager for which travels up on the 15:55.
Various departures were held up (even for the Met line) to allow the 18:07 to depart as quickly as possible, it was about 15 late away. The knock-on was horrendous, affecting a raft of services from 18:00 onwards. The 18:16 Bicester North was cancelled completely - presumably the 172s were defective, they didn't make it off the wall siding.
I don't know what time things got back to normal but a better contingency plan needs to be put in place. Were a train manager available then it could have been possible to step up the Banbury loco-hauled to cover the 18:07 diagram (albeit with shoddy stock - but it's happened before) and the incoming train could have been used for the Banbury, with plenty of time over the weekend to reposition the sets for Monday.