BA 174 then BA 870 at Heathrow
New York JFK → London → Budapest
Timetable, London time
06:40BA 174 from New York JFK at the gate
19:25BA 870 to Budapest leaves the gate
12 h 45 apart on the timetable
BA 870 leaves 12 h 45 after BA 174 arrives on the timetable: more than half a day, so not a connection we count.