UA 27 then BA 492 at Heathrow
Denver → London → Gibraltar
Timetable, London time
09:40UA 27 from Denver at the gate
08:10BA 492 to Gibraltar leaves the gate
22 h 30 apart on the timetable, overnight
BA 492 leaves 22 h 30 after UA 27 arrives on the timetable: more than half a day, so not a connection we count.