BA 865 then BA 580 at Heathrow
Prague → London → Milan
Timetable, London time
08:15BA 865 from Prague at the gate
07:45BA 580 to Milan leaves the gate
23 h 30 apart on the timetable, overnight
BA 580 leaves 23 h 30 after BA 865 arrives on the timetable: more than half a day, so not a connection we count.