BA 903 then BA 468 at Heathrow
Frankfurt am Main → London → Madrid
Timetable, London time
17:15BA 903 from Frankfurt am Main at the gate
16:25BA 468 to Madrid leaves the gate
23 h 10 apart on the timetable, overnight
BA 468 leaves 23 h 10 after BA 903 arrives on the timetable: more than half a day, so not a connection we count.