BA 853 then BA 746 at Heathrow
Prague → London → Geneva
Timetable, London time
12:30BA 853 from Prague at the gate
10:30BA 746 to Geneva leaves the gate
22 h apart on the timetable, overnight
BA 746 leaves 22 h after BA 853 arrives on the timetable: more than half a day, so not a connection we count.