'MarconiPhone' Television Receiver
This receiver is a unique early version of the HMV 902 series of which only eleven were manufactured. Its importance stems from the fact that it is a dual-standard set, designed to receive television transmission on both the Marconi-EMI 405-line system, later adopted as the standard, as well as the Baird 240-line system.The receiver was in use when the world's first public, high-definition television service was launched from Alexandra Palace. It is the only surviving receiver capable of displaying the Baird system of 240-line pictures.
Source:
http://www.nmsi.ac.uk/review/keyaqnmp.htm