BA 549 then BA 584 at Heathrow
Rome → London → Milan Linate
Timetable, London time
14:05BA 549 from Rome at the gate
13:15BA 584 to Milan Linate leaves the gate
23 h 10 apart on the timetable, overnight
BA 584 leaves 23 h 10 after BA 549 arrives on the timetable: more than half a day, so not a connection we count.