FR 3040 then U2 2326 at Barcelona
Prague → Barcelona → London Luton
Timetable, Barcelona time
21:55FR 3040 from Prague at the gate
20:55U2 2326 to London Luton leaves the gate
23 h apart on the timetable, overnight
U2 2326 leaves 23 h after FR 3040 arrives on the timetable: more than half a day, so not a connection we count.