UL 505 then BA 846 at Heathrow
Colombo → London → Warsaw
Timetable, London time
08:40UL 505 from Colombo at the gate
11:55BA 846 to Warsaw leaves the gate
3 h 15 apart on the timetable
The last days
UL 505 and BA 846 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.