1. The owner of land abutting tidal water is presumed to own it down to the mean high water mark. But this does not include the foreshore (the area between mean high and low water marks). Since the foreshore may well move with the sea, it follows that the foreshore is a movable freehold (growing or decreasing with nature).

2. It is presumed that the bed of all tidal fl ows of water, whether rivers or the sea, belong to the Crown (although, these days, 45% of the foreshore is now owned by other bodies).

Accretion is the gaining of land as a result of the gradual change in the mean high water level (and losing such land is known as erosion). As the high water mark changes, so the boundaries change – irrespective of what may be shown on old title deeds or on OS plans. However, the accretion rule only applies to acts of nature; it does not apply to deliberate acts (eg the building of a wall which then alters the foreshore). See [2008] 207 Property Law Journal 18 © Practical Lawyer