BA 487 then BA 1498 at Heathrow
Barcelona → London → Glasgow
Timetable, London time
21:35BA 487 from Barcelona at the gate
21:00BA 1498 to Glasgow leaves the gate
23 h 25 apart on the timetable, overnight
BA 1498 leaves 23 h 25 after BA 487 arrives on the timetable: more than half a day, so not a connection we count.