Camden Lock, or Hampstead Road Locks is a twin manually-operated lock on the Regent's Canal in Camden Town, London Borough of Camden. The sign identifying the lock reads "Hampstead Road Lock". The locks were constructed between 1818–20 by James Morgan, with John Nash, supervising engineer. It is the only twin-lock remaining on the Canal, the remainder having been modified to single lock operation. The current locks are Grade II listed and replaced an innovative hydropneumatic lock designed by William Congreve in an attempt to conserve water, which was a failure. The lock is to the west of the Camden High Street road bridge. The yard and former warehouses, an area known as Camden Lock, are on the north side of the canal, at the junction with Chalk Farm Road. This area is adjacent to a canal basin and holds Camden Lock Market, one of the group of markets often called collectively Camden Market. It is a busy market popular with visitors, with music venues, cafes and canal towpath walks.