From this site Guglielmo Marconi made the first public transmission of wireless signals on 27 July 1896.
Site: Marconi - EC1 (1 memorial)
EC1, Newgate Street
2019: The  reported that BT have announced their plan to sell this site. The building only dates from 1984 but BT (GPO) have been on the site for over a century.
Comments are provided by Facebook, please ensure you are signed in to see them