BA 483 then BA 724 at Heathrow
Barcelona → London → Zurich
Timetable, London time
19:25BA 483 from Barcelona at the gate
19:10BA 724 to Zurich leaves the gate
23 h 45 apart on the timetable, overnight
BA 724 leaves 23 h 45 after BA 483 arrives on the timetable: more than half a day, so not a connection we count.