In Malibu, private owners and developers have battled public access to the California coastline, every inch of which is public property. They've employed all the means described in the Guardian article to discourage public access: locked gates, blocked pathways, private security guards, intimidating signs, and CCTV.
An incredible smartphone app called "Our Malibu Beaches" has put more power into the hands of the public. The app clearly shows all public access paths to the beaches, the existence of which private owners have tried to disguise with huge plantings, boulders, fake driveways, and locked gates. The app also describes, property by property, how many feet of dry sand belong to the public (all wet sand is public). In many cases, homeowners have granted public easements of 10, 20, and 30 feet of dry sand in front of their houses in return for permits to develop their properties. The app shows where all the public easements are, to the great dismay of the property owners.
Perhaps a tech-savvy public-access enthusiast could write such an app for the Thames pathways? Information is power.
http://www.nytimes.com/2013/06/13/us...ks-access.html