BA 611 then BA 486 at Heathrow
Palermo → London → Barcelona
Timetable, London time
15:10BA 611 from Palermo at the gate
14:00BA 486 to Barcelona leaves the gate
22 h 50 apart on the timetable, overnight
BA 486 leaves 22 h 50 after BA 611 arrives on the timetable: more than half a day, so not a connection we count.