BA 973 then BA 678 at Heathrow
Berlin → London → Istanbul
Timetable, London time
10:55BA 973 from Berlin at the gate
10:30BA 678 to Istanbul leaves the gate
23 h 35 apart on the timetable, overnight
BA 678 leaves 23 h 35 after BA 973 arrives on the timetable: more than half a day, so not a connection we count.