var vtn_player_type = "vp";var ven_video_key="NTgzOTg3fHwxNDcxfHwwfHx8fHx8";var ven_width="660";var ven_height="409";London's iconic red telephone boxes are going green as the first "Solarbox" is unveiled at Tottenham Court Road tube station. Duration: 00:51