A new film centred on a man’s battle with powerful developers in Hampstead has attracted an A-list cast – with the tale having stark similarities to the true story of a squatter’s war over a patch of land on the Heath.

Ham & High: Harry Hallowes lived in a shack on the Heath for 20 years before gaining the land under squatter's rightsHarry Hallowes lived in a shack on the Heath for 20 years before gaining the land under squatter's rights (Image: Archant)

The aptly-named Hampstead is to star Emmy Award-winner Brendan Gleeson (Calvary, Harry Potter) and Academy Award-winner Diane Keaton (Annie Hall, The Godfather).

The “heartwarming romance”, inspired by true events, centres on Emily Walters (Keaton), a woman living on the edge of the Heath who is “drifting through life without much thought to her future”.

The film sees her encounter an “unkempt man”, Donald Horner (Gleeson), who has been quietly living in a ramshackle hut on the Heath for the past 17 years.

But when developers start using heavy-handed tactics to remove him, Walters befriends Horner and the pair take up the fight together.

While not confirmed by the company behind the film, the story shares remarkable similarities with that of Harry “the hermit” Hallowes, an Irish squatter who became the legal owner of a prime spot of Hampstead Heath where he had lived in a shack for 20 years.

The plot of land formed part of the grounds of Athlone House, an historic Highgate mansion perched on the edge of Hampstead Heath.

In 2005, a developer wanting to turn the mansion into flats tried but failed to evict Mr Hallowes.

In 2007, he won a court battle and gained the £2million plot under squatters rights.

Mr Hallowes is still said to live on the plot, which forms part of a nature reserve for snakes.

However, one element of the film’s re-telling of the story could prompt anger from residents.

The screenplay sees a group of local campaigners battle on the side of the developers.

Michael Hammerson, who tirelessly leads the campaign against the development of Athlone House, described as “almost libellous” the suggestion the local community sided with the developers.

It could also anger filmmaker and Highgate resident Terry Gilliam, another vocal campaigner against the demolition of the 19th century mansion.

Directed by Bafta Award-winner Joel Hopkins, film crews are expected to descend on the Heath early next year.