FR 3929 then U2 2324 at Barcelona
Trieste → Barcelona → London Luton
Timetable, Barcelona time
10:50FR 3929 from Trieste at the gate
10:35U2 2324 to London Luton leaves the gate
23 h 45 apart on the timetable, overnight
U2 2324 leaves 23 h 45 after FR 3929 arrives on the timetable: more than half a day, so not a connection we count.