Worthing Borough Council manages the gardens, which benefited from a £1m National Lottery funding boost last June to regenerate the eight-and-a-half-acre beauty spot.

Cllr Vicki Wells, Cabinet Member for the Environment, Worthing Borough Council, said: “We are hugely saddened that somebody has deliberately damaged one of the historic trees at Highdown Gardens.

“Highdown Gardens is there to be enjoyed by everyone, not just now but in decades to come. Deliberate damage to any of these trees is completely unacceptable as it can cause disease and their premature death. Importantly, deliberate damage is a criminal offence and those found guilty will face legal action. So if you see anyone damaging any of these trees, please report it.”

Stripping a tree of its bark denies it access to vital nutrients, while also lessening its natural protection from both animals and the elements and denying it the chance to grow branches and putting the tree under great stress.

The chalk gardens have been managed by Worthing Borough Council since they were handed over for the benefit of local residents more than 50 years ago.

Situated in the South Downs countryside between Durrington and Angmering overlooking the sea, the gardens are free to visit and are currently open from 10am till dusk.

They are home to The National Plant Collection of the plant introductions of Sir Fredrick Stern - a unique collection of unusual plants and trees to be discovered all year round.