BA 549 then TP 1359 at Heathrow
Rome → London → Lisbon
Timetable, London time
14:05BA 549 from Rome at the gate
13:40TP 1359 to Lisbon leaves the gate
23 h 35 apart on the timetable, overnight
TP 1359 leaves 23 h 35 after BA 549 arrives on the timetable: more than half a day, so not a connection we count.