AI 187 then BA 553 at Fiumicino
New Delhi → Rome → London Heathrow
Timetable, Rome time
02:40AI 187 from New Delhi at the gate
14:55BA 553 to London Heathrow leaves the gate
12 h 15 apart on the timetable
BA 553 leaves 12 h 15 after AI 187 arrives on the timetable: more than half a day, so not a connection we count.