Itsu sushi restaurant, 167 Piccadilly, London W1J 9EG, nearly opposite Old Bond Street.
Itsu featured in the early media speculation as the place where Litvinenko met Mario Scaramella, an Italian academic / spook with whom he had been working The restaurant is now so popular with tourists, that it is expanding into the adjacent mobile phone shop premises.
GPS grid coordinates:
Latitude: (WGS84) N51:30:28 ( 51.507806 )
Longitude: (WGS84) W0:08:23 ( -0.139784 )