EC 3749 then BA 485 at Barcelona
Milan → Barcelona → London Heathrow
Timetable, Barcelona time
08:40EC 3749 from Milan at the gate
17:00BA 485 to London Heathrow leaves the gate
8 h 20 apart on the timetable
The last days
EC 3749 and BA 485 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.