FR 6926 then U2 2326 at Barcelona
Rome → Barcelona → London Luton
Timetable, Barcelona time
21:10FR 6926 from Rome at the gate
20:55U2 2326 to London Luton leaves the gate
23 h 45 apart on the timetable, overnight
U2 2326 leaves 23 h 45 after FR 6926 arrives on the timetable: more than half a day, so not a connection we count.