BA 391 then BA 466 at Heathrow
Brussels → London → Madrid
Timetable, London time
16:20BA 391 from Brussels at the gate
15:00BA 466 to Madrid leaves the gate
22 h 40 apart on the timetable, overnight
BA 466 leaves 22 h 40 after BA 391 arrives on the timetable: more than half a day, so not a connection we count.