Mike Leigh’s brilliant 1976 Dorset-based comedy Nuts in May begins with Keith and Candice-Marie taking the chain ferry from Sandbanks across the mouth of Poole harbour to the Isle of Purbeck, where they camp, visit Corfe Castle, walk along the mighty Jurassic coastline and end up in an altercation with a young Brummie couple called Finger and Honky. For me, watching Nuts in May is an annual tradition, as is visiting the peninsula where it was filmed. Most of us have places for which we feel a particularly strong pull; one of mine is Purbeck. And since this peninsula’s recent status as England’s first “super” nature reserve, I’m beginning to understand why.

Being a relatively remote peninsula, Purbeck has seen little major development over the past 70 years, despite its south coast location. On a human scale, the landscape is relatively unchanged since Keith and Candice-Marie’s ill-fated camping trip half a century ago. Behind the scenes, however, years of conservation work from seven organisations – including the National Trust, RSPB, Dorset Wildlife Trust and Natural England – has led to the creation of a near-continuous jigsaw of restored habitats, making it the UK’s first designated super nature reserve, running clockwise from Brownsea Island and the Studland peninsula to Arne, further west on Poole harbour.

The removal of fences has allowed for continuous grazing: pigs, cattle, ponies, donkeys have free rein across 1,300 hectares; don’t be surprised to see them lazing on the roads, woodlands and in the heathland. This work, combined with Purbeck’s broad mix of habitats – from the limestone cliffs at Durlston and Kimmeridge to downland, heathland, the harbour and sandy beaches – have led to this peninsula being cited as having the greatest biodiversity in England. According to Peter Robertson, senior site manager at RSPB Arne, while most conservation work is based around slowing the decline of biodiversity, here it’s actually on the rise.

The crowning glory of Purbeck’s biodiversity – and an area often overlooked by visitors – is the northern peninsula of Arne, which combines healthland, ancient woods, secluded beaches, estuaries and the southern reaches of Poole harbour. Here it is hoped that ospreys and white-tailed eagles will breed this year. The RSPB reserve is a great place to see other raptors, including harriers and goshawks, as well as waders, spoonbills, terns and ground-nesting reptiles and birds such as nightjars, stone chats, sand lizards and woodlarks. On a late warm spring or summer evening the churring of nightjars is a common sound; to encounter these prehistoric-looking birds makes for an enchanting experience. A good place to see them is Hyde’s Heath at dusk. On a different part of the reserve, Coombe Heath, walkers can enjoy good views of osprey feeding stations by the estuary, with a modest-size pond home to wasp and raft spiders.

Purbeck marks the end (or beginning) of the South West Coast Path and includes two remarkable chalk sea stacks: Old Harry Rocks and the natural arch of Durdle Door. Inland, all roads lead to Corfe Castle. Its iconic 11th-century ruin sits on a steep hillock between two higher slopes. Often busy with traffic and people, Corfe is home to a model village, an excellent ice-cream parlour and one of four stations for Purbeck’s steam train, which runs from Swanage to Norden. The Scott Arms in Kingston is a huge stone-built inn with a beer garden overlooking the heathland and Corfe Castle that serves hearty pub fare, and at weekends from Easter to September its seasonal Jamaican chefs open JerkShak in the garden, serving delicious jerk chicken, callaloo and ackee and saltfish.

Purbeck’s only serious contender for the title of “all-round best pub” is the 18th- century Square & Compass in Worth Matravers. What this alehouse lacks in the way of a bar – there’s only a small hatch for collecting drinks – it makes up for with its enviable location. It offers sea views and sunsets, award-winning ales and ciders, and regular folk sessions in the main room with an open fire.

At the far end of the Square & Compass is a fossil museum with cabinets containing shark remains, crocodile teeth, ammonites and dinosaur poo. The museum serves as a reminder that, being part of the Jurassic Coast, Purbeck is rich in prehistoric discoveries and fossils: an impressive series of dinosaur footprints can be found at Kearnes Quarry, just off Priest’s Way and Spyway near Acton. The most comprehensive range of fossils from the whole of the Jurassic Coast however, is at Etches Museum in Kimmeridge, a village that gained national fame after a pliosaur skull was discovered poking out of a sheer cliff edge in 2022. The subsequent BBC programme that told the story of its discovery, David Attenborough and the Giant Sea Monster, helped put the museum on the map. Artfully displayed are a mix of donations and the 40-year collection of fossil expert Steve Etches that includes the world’s first ammonite eggs, a pterosaur skull and the world’s largest remains of a Kimmerosaurus.

I spend most of my Purbeck evenings at the Bankes Arms in Studland, the Kings Arms in Langton Matravers or the Square & Compass, watching the sun set over the Jurassic Coast with a pint of Otter Head, a pasty and falling into a random conversation with strangers about Tiny Tim, Cathar heretics and how best to grow artichokes. During the day however, I’m walking the heathland, moors, cliffs and woodlands, not just for scenery but – being a keen birder – also for the wildlife. With the chance to see bottlenose dolphins, fulmars, razorbills, guillemots and carpets of orchids, I follow the stunning coastal cliffs west from Durlston country park, then east from Dancing Ledge, where a small breeding population of puffins can still be found.

On Studland Dunes and the neighbouring heath, which runs from South Beach to Knoll Beach, I keep my eyes peeled for reptiles. All six of our native species – including the sand lizard and the rare smooth snake – can be found here, as can Dartford warblers, flycatchers and mining wasps.

“My business is to protect the life in our countryside and our heritage,” cries Keith near the end of Nuts in May, when attempting to stop the ignorant young Finger from lighting a fire where he shouldn’t. Back in 1976 part of the “oddball” nature of Roger Sloman and Alison Steadman’s comic characters was that they were environmentalists and vegetarians who refused to eat factory-farmed eggs. Nowadays these are qualities and lifestyle choices that most of us have come to respect.

Thanks to decades of work by environmentalists, the RSPB, wildlife charities, conservationists and reptile trusts – whose daily business really is to protect the life in the countryside and our heritage – insects, birds, reptiles and flora are becoming more abundant on Purbeck. Reason enough to fall in love with this beautiful corner of Dorset. That, and the odd pint of Otter Head.