BA 172 then BA 594 at Heathrow
New York JFK → London → Venezia
Timetable, London time
08:35BA 172 from New York JFK at the gate
08:05BA 594 to Venezia leaves the gate
23 h 30 apart on the timetable, overnight
BA 594 leaves 23 h 30 after BA 172 arrives on the timetable: more than half a day, so not a connection we count.