BA 339 then BA 5 at Heathrow
Nice → London → Tokyo
Timetable, London time
12:15BA 339 from Nice at the gate
11:40BA 5 to Tokyo leaves the gate
23 h 25 apart on the timetable, overnight
BA 5 leaves 23 h 25 after BA 339 arrives on the timetable: more than half a day, so not a connection we count.