however, there were legal problems and these delayed the permission that was needed to build the subway and tram route. permission to build the subway was not given until 1906, and they were still not allowed to build the tram line over the bridge. the tunnel would also only be able to have single-deck trams in it. this was because of a sewer at the northern end of the tunnel and the district railway at the southern end. when the trams left the subway at the southern end, they could turn right along the embankment to westminster bridge, or left on a service from bloomsbury to the hop exchange. this latter service was short-lived and the tracks were removed in 1930.