Damage to my property and trespass

I am the freeholder of a lot of Hensington Gate and specifically the land and paths on hedge end and behind hedge end... I have my land registry plan and I have visited the site regularly over the past 30 years on my own behalf and the previous 10 for the previous freeholder..... My freehold shows a fence on my boundary and the fence is physically in situ... previously I have repaired this fence...recently I visited the site to find that my fence has been cut in two places and an access has been created where I have shown on the map and further up at the back of 29 Plane Tree Way. This would appear to be a trespass and we are presently in discussions with the developer of houses on the newly created Youngs Way and Durston Rise for them to reinstate the fence... no one could have gain a prescriptive right to access my property and so I need to understand what part the council play in this, please. kind regards Matthew Dietz