FR 3040 then U2 2324 at Barcelona
Prague → Barcelona → London Luton
Timetable, Barcelona time
21:15FR 3040 from Prague at the gate
10:25U2 2324 to London Luton leaves the gate
13 h 10 apart on the timetable, overnight
U2 2324 leaves 13 h 10 after FR 3040 arrives on the timetable: more than half a day, so not a connection we count.