BA 483 then AC 859 at Heathrow
Barcelona → London → Toronto
Timetable, London time
19:25BA 483 from Barcelona at the gate
18:00AC 859 to Toronto leaves the gate
22 h 35 apart on the timetable, overnight
AC 859 leaves 22 h 35 after BA 483 arrives on the timetable: more than half a day, so not a connection we count.