BA 581 then BA 780 at Heathrow
Milan → London → Stockholm
Timetable, London time
13:55BA 581 from Milan at the gate
13:20BA 780 to Stockholm leaves the gate
23 h 25 apart on the timetable, overnight
BA 780 leaves 23 h 25 after BA 581 arrives on the timetable: more than half a day, so not a connection we count.