A National Rail station was eventually constructed on the site, but to serve the north-south Thameslink route, rather than the originally envisaged east-west line. Also, the station was not named Ludgate Circus, but rather St Paul's Thameslink, later changed to City Thameslink due to confusion with the nearby St Paul's Underground station. It was however built in such a way as to allow for an underground east-west aligned station to be easily integrated; this can be seen in the wide spaces on the Ludgate end of the station, where large doors open on to a corridor intended to lead to escalators to a Underground concourse level. It is still known today as the LUL corridor by staff.