BA 721 then EK 4 at Heathrow
Zurich → London → Dubai
Timetable, London time
20:25BA 721 from Zurich at the gate
20:20EK 4 to Dubai leaves the gate
23 h 55 apart on the timetable, overnight
EK 4 leaves 23 h 55 after BA 721 arrives on the timetable: more than half a day, so not a connection we count.