Flight Pulkovo Airport Saint Petersburg departs from St. Petersburg Pulkovo Airport Saint Petersburg at 14:30 and arrives at London Heathrow Airport at 16:00.
The flighttime is about 3h 30m. The distance travelled ("as the bird flies"): 3528 Km. So the average speed is roughly 1008 Km.
There is an 2 hour time difference between St. Petersburg and London