If you've ever applied for a trademark, you'll have received a few letters from various "Registers" with official sounding names. They appear to be invoicing you for official filing fees but in reality they're a cynical, prospective invoicing scam charging you for inclusion in worthless online and printed directories. This latest one is actually criminal - the scammer is impersonating the UK Intellectual Property Office itself. If you've used a trademark lawyer to file your application, ignore any letters you receive from anyone else as your lawyer will pass on official communications. If you applied yourself, you can check that any request for payment or information is official by calling the IPO directly on 0300 300 2000.