 This is the usual tidal limit; however, high spring tides can raise the head water level in the reach above Teddington and can occasionally reverse the river flow for a short time.In these circumstances, tidal effects can be observed upstream to the next lock beside Molesey weir, which is visible from the towpath and bridge beside Hampton Court Palace.Before Teddington Lock was built in 1810–12, the river was tidal at peak spring tides as far as Staines upon Thames.