FR 2508 then U2 2324 at Barcelona
Cologne → Barcelona → London Luton
Timetable, Barcelona time
11:05FR 2508 from Cologne at the gate
10:25U2 2324 to London Luton leaves the gate
23 h 20 apart on the timetable, overnight
U2 2324 leaves 23 h 20 after FR 2508 arrives on the timetable: more than half a day, so not a connection we count.