BA 475 then BA 964 at Heathrow
Barcelona → London → Hamburg
Timetable, London time
13:10BA 475 from Barcelona at the gate
17:10BA 964 to Hamburg leaves the gate
4 h apart on the timetable
The last days
BA 475 and BA 964 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.