through services started on 10 april 1908. they ran from highbury station to tower bridge and to kennington gate. there was a procession of six cars that went south from the holborn through to kennington. they then diverted to elephant and castle in order to return through the subway to angel. the kennington service was not commercially viable and services were diverted to operate to queens road in battersea. due to a low bridge, this service could only be operated with single-deck vehicles. drivers of the trams recorded difficulty in climbing the ramp north from holborn tramway station and would sometimes roll all the way back to the station. drivers on routes through the tunnel had to have at least two years experience on other services to be considered for these routes.