I used to work for Sony Computer Entertainment at the EU HQ in London, there were a few games studios there, all located around the same street just off Oxford Circus, along with a big R&D office.

I think the London Studio is still there, not sure what they are working on now though.

King who make candy crush are near there too, I went for a job interview with them around 6 years ago, you could tell at that time, judging by the offices, they were not strapped for cash...