The majority of cloakrooms and en-suites in the UK are built with very little room to spare so space is always at a premium.
Wall mounted corner basins take up very little wall space and do not take up any floor-space so they are an ideal choice in these situations. There are wall mounted versions and corner basins with pedestals.
The current trend towards designer glass basins has meant that even these are available in corner mounted versions specifically designed to have a minimal impact on the overall space.
Corner baths and shower enclosures have been around for ages but bathroom manufacturers have realised the advantages of siting other bathroom components in the corner of the room so there are now corner mounted toilets available as well as many bathroom storage solutions such as corner bathroom cabinets.