I have seen this one before about a month ago.
This Thomson B738 was actually enroute from Sharm el Sheik to Cardiff and seems to be descending directly along the centreline of runway 09R at London Heathrow, but at FL330. I just wish that I had spotted it a few seconds earlier.
The plane that is taking off is probably the last departure of the day from Heathrow.
Well spotted, Roland - nice one :-)
Rod