BA 595 then BA 588 at Heathrow
Venezia → London → Milan
Timetable, London time
15:40BA 595 from Venezia at the gate
15:20BA 588 to Milan leaves the gate
23 h 40 apart on the timetable, overnight
BA 588 leaves 23 h 40 after BA 595 arrives on the timetable: more than half a day, so not a connection we count.