BA 893 then BA 406 at Heathrow
Sofia → London → Cairo
Timetable, London time
21:50BA 893 from Sofia at the gate
21:25BA 406 to Cairo leaves the gate
23 h 35 apart on the timetable, overnight
BA 406 leaves 23 h 35 after BA 893 arrives on the timetable: more than half a day, so not a connection we count.