A3 877 then A3 608 at Athens
Budapest → Athens → London Heathrow
Timetable, Athens time
19:20A3 877 from Budapest at the gate
19:10A3 608 to London Heathrow leaves the gate
23 h 50 apart on the timetable, overnight
A3 608 leaves 23 h 50 after A3 877 arrives on the timetable: more than half a day, so not a connection we count.