U2 8446 then U2 8065 at Gatwick
Nantes → London → Barcelona
Timetable, London time
11:40U2 8446 from Nantes at the gate
09:10U2 8065 to Barcelona leaves the gate
21 h 30 apart on the timetable, overnight
U2 8065 leaves 21 h 30 after U2 8446 arrives on the timetable: more than half a day, so not a connection we count.