UA 5 then BA 756 at Heathrow
Houston → London → Basel
Timetable, London time
10:15UA 5 from Houston at the gate
09:25BA 756 to Basel leaves the gate
23 h 10 apart on the timetable, overnight
BA 756 leaves 23 h 10 after UA 5 arrives on the timetable: more than half a day, so not a connection we count.