A quote regarding Gann v. Free Fishers of Whitstable (1865) from this document.

Common property resources are those resources not controlled by a single entity and access to which is limited to an identifiable community of individuals or states. No one user has the right to abuse or dispose of the property. Any dealing with the property has to take into account the entitlements of others. Besides, users of common property share rights to the resource and are subject to rules and restrictions governing the use of those resources.7In England, this concept appears in the common law, particularly through the writings of Bracton and Flecta, Englandís Magna Carta, and commentary by Blackstone. These sources are cited as precedent for the notions of common rights to navigation and fishing, but again questions arise over whether these statements accurately reflect the practices of the time given the prevalence of private fisheries. Paragraph 5 of the Magna Carta made explicit reference to the guardianship of land extending the guardianship to houses, parks, fish ponds, tanks, mills and other things pertaining to land. As early as 1865, the English House of Lords defined the concept of public trust in the case of Gann v. Free Fishers of Whitstable holding that the bed of all navigable rivers here the tide flows, and all estuaries or arms of the sea, is by law vested in the crown. But this ownership of the crown is for the benefit of the subject, and cannot be used in any manner so as to derogate from, or interfere with the right of navigation, which belongs by law to the subject of realm.
And

In further elaborating the concept of public trust, the English Common Law distinguished between property that was transferable to private individuals (jus privatum) and property that was held in trust for the public (jus publicum) Ė traditionally mainly navigable waterways. Jus publicum is the dominant estate and encapsulates the publicís trust rights, ranging from fishing, fowling and navigation to other broader rights like recreation.12 The second component, the jus privatum encompasses the proprietary rights for use and possession of property. Naturally the owners of the jus privatum may not use the property of the jus publicum to the exclusion of the publicís rights.
I believe the Gann v. Free Fishers of Whitstable judgement was one of the pivotal cases that Doug Caffyn used in his evidence for his thesis. It looks to be a pretty darn strong case against the claims of the angling associations and riparians to me. The idea that they merely hold the rivers in trust under common law rather than actually owning the resource is a compelling one. Given that the Gann v. Free Fishers of Whitstable case appears to have set a precedent, does anyone know of a case that overturned the legal interpretation reached in that judgement?