In Port of London Authority v Ashmore, the High Court had to decide whether the owner of a boat moored against the bank of the River Thames in London had acquired title to part of the riverbed by adverse possession.

Title to the riverbed and the space above it was unregistered, and Mr Ashmore's boat had been moored in the same spot for more than 12 years (the limitation period for unregistered land). The boat was tethered to mooring rings set into the riverbank and also secured by an anchor in the usual way. Twice a day, at low tide, it came to rest on the riverbed; for the rest of the time it was afloat.

In order to make out a claim in adverse possession, the claimant must show (i) a sufficient degree of physical custody and control ("factual possession") and (ii) an intention to exercise such custody and control on the claimant's own behalf and for his own benefit ("intention to possess").

On (i), the court ruled that what actions will constitute a sufficient degree of exclusive possession depends on the nature of the land and the manner in which land of that nature is commonly used. A squatter can be in continuous possession even if he does not use the land continually. In addition, possession of one part of an area can in certain circumstances be treated as constituting possession of the whole area. In this case, the fact that the boat rose and fell with the flowing and ebbing of the tide did not mean that Mr Ashmore relinquished physical possession of the land on which the boat rested at low tide. In any event, the boat's anchor was always in contact with the riverbed.

The court also thought that Mr Ashmore had the necessary intention to possess. On that basis his claim to title by adverse possession succeeded.

However, the vessel's position at its mooring would not have remained static but would have moved with the wind and the tide. The court therefore had to consider the extent of the land acquired by Mr Ashmore. It ruled that this included the total area between the extreme points where the boat had had contact with the riverbed over the years, together with the space above the bed through which the river flowed, and the air to a reasonable height above that. It also included the area beneath the outline of the deck, even though the boat only rested over that part of the riverbed and not on it, and arguably (though the court did not express a definite view on the point) the space between the boat and the riverbank.

Things to consider

The facts of this case are obviously not something that property professionals come across every day. However, one wonders how many other boat owners are in a similar position and whether a "flood" of claims will follow... On that basis the case serves to emphasise to all landowners to take swift action against those who may be trespassing on their land to either evict or regularise their occupation, in order to prevent a claim based on adverse possession from arising.

The judge was careful to restrict the ambit of his decision to vessels moored adjacent to the bank of a tidal river. He offered no opinion on whether the outcome of the case could also be applied to vessels moored away from the riverbank, in a non-tidal river or even at sea. Another point to note is that, since the foreshore and riverbed of the tidal part of the Thames is owned by the Port of London Authority, the usual limitation period for unregistered land of 12 years applied to Mr Ashmore's claim. Most foreshore in England & Wales belongs to the Crown; to which a limitation period of 60 years applies.

Although the part of the river occupied by Mr Ashmore is subject to a public right of navigation, the Port of London Authority conceded that of itself this would not prevent Mr Ashmore from obtaining title by adverse possession. This makes for an interesting contrast with the case of R (on the application of Smith) v The Land Registry and Cambridgeshire County Council, considered in April's property update. Mr Smith made an application for first registration based on adverse possession of a piece of land which was a public highway. His claim was rejected on the basis that the adverse possession rules could not override the criminal offence created by his obstruction of the highway. The court in Port of London Authority v Ashmore stated that it had not explored the consequence of that part of the river being subject to a public right of navigation because of the Authority's concession, but noted that the existence of the right may mean that the ruling in favour of Mr Ashmore would be a "pyrrhic victory".