BA 349 then BA 870 at Heathrow
Nice → London → Budapest
Timetable, London time
21:05BA 349 from Nice at the gate
19:25BA 870 to Budapest leaves the gate
22 h 20 apart on the timetable, overnight
BA 870 leaves 22 h 20 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.