This is a strange fragment of demolished, at the time grandiose station and hotel, Highbury & Islington. Next to it are heavy metal doors ‘licences storage’. To see the original glory of the station see here c1910: https://www.flickr.com/photos/36959568@N02/5673489996/ and here 1956 (shortly after this picture was taken it was demolished – in the 60s): https://www.flickr.com/photos/36959568@N02/3650091765/.