Helen Mark travels to Sussex to explore the wilderness at Knepp Castle Estate. Isabella Tree and her husband Charlie Burrell have turned their estate which was once intensively farmed over to a rewilding project since 2001. Isabella takes Helen to her favourite part of the landscape which has undergone the greatest change since they started restoring the land back to it's natural and uncultivated state.

Helen also goes bird ringing and cattle mustering on the state, now home to long horns, free roaming deer, pigs and Exmoor ponies. She meets a couple who retired and moved to the South Downs for an idyllic country life only to discover the view from their house is more than they bargained for. So is re-wilding the estate really working and should we be doing it?

The producer is Peminder Khatkar.