FR 4584 then BA 473 at Barcelona
Porto → Barcelona → London Heathrow
Timetable, Barcelona time
11:05FR 4584 from Porto at the gate
10:15BA 473 to London Heathrow leaves the gate
23 h 10 apart on the timetable, overnight
BA 473 leaves 23 h 10 after FR 4584 arrives on the timetable: more than half a day, so not a connection we count.