QR 3746 then U2 2326 at Barcelona
Milan → Barcelona → London Luton
Timetable, Barcelona time
21:20QR 3746 from Milan at the gate
20:55U2 2326 to London Luton leaves the gate
23 h 35 apart on the timetable, overnight
U2 2326 leaves 23 h 35 after QR 3746 arrives on the timetable: more than half a day, so not a connection we count.