BA 483 then BA 818 at Heathrow
Barcelona → London → Copenhagen
Timetable, London time
19:25BA 483 from Barcelona at the gate
18:45BA 818 to Copenhagen leaves the gate
23 h 20 apart on the timetable, overnight
BA 818 leaves 23 h 20 after BA 483 arrives on the timetable: more than half a day, so not a connection we count.