The world’s shortest scheduled flight, from the small Orkney island of Westray to the smaller island of Papa Westray, lasts just two minutes. Anyone who has been to the Orkney Islands, off the north coast of Scotland, can tell you that. It is, writes Patrick Barkham, “the fact about Orkney repeated by every visitor”.

In Islander – a journey around our archipelago, the author and Guardian natural history writer visits 12 islands around Britain, seeking to discover “the essence of what it is to be an islander”. He starts on the Isle of Man (population 85,000) and travels to progressively smaller islands before ending up on Ray in Essex (population 0).

Barkham’s journey is all small planes and rough crossings, beaten-up Peugeots and tiny Suzukis. As well as the world’s shortest flight, Scotland’s islands also boast the world’s only airport where scheduled flights use a beach as a runway, Barra’s Traigh Mhòr.

Islands have a way of developing unique features. Take the sparrow-sized St Kilda wren or the Orkney vole, which caused the world’s first and only vole tourist boom after it was wrongly declared a new species in 1904. Genetic studies in the 1950s established that it was only a subspecies of the common vole but, says Barkham, this is no less thrillingly strange because the common vole does not – and probably never did – exist on the British mainland.

Barkham dedicates a chapter to each island he visits. The connecting thread is provided by Compton MacKenzie. A prolific if largely forgotten novelist, MacKenzie inspired DH Lawrence’s short story The Man Who Loved Islands and lived and wrote on many of the islands visited by Barkham.

In Lawrence’s story, a young idealist acquires a small island as a sanctuary and soon learns an “inescapable truth”: living on a rock surrounded by the ocean is prohibitively expensive. He downsizes continuously until he finally ends up in a concrete hut on a bleak rock, living first with a cat, then alone, before he finally goes mad and dies.

Barkham wants to find out if Lawrence is correct – that islands are dangerously seductive places for people seeking to escape the mainstream but who swiftly discover they cannot escape themselves.

On Man, he finds an island seductive to people seeking to escape bothersome revenue officials. When the British empire crumbled, Man and the Channel Islands provided returning colonialists with an idealised, low-tax version of home. But the new arrivals failed to endear themselves to their hosts and soon earned the nickname “When-I”s, as in, “When I was in Uganda we wouldn’t stand for this sort of thing”.

Despite the initial discord, Man went on to overcome a period of population decline and by the 1970s was thriving. More recently it has become home to a variety of online gambling companies who require little other than a reliable internet connection.

The internet emerges as a lifeline for many smaller islands. “Suddenly, lots of people can do office jobs without making a daily commute to the city,” remarks a resident on Eigg in the Inner Hebridies. “There is no requirement for a century of centralisation to continue into the digital age.”

But the real barometer of island life is the school. On Rathlin, off the coast of Antrim, Barkham meets wildlife warden Liam McFaul who remembered electricity coming to the island in 1993. “I grew up with an oil lamp and a car battery powering a black and white TV,” he recalls.

In the intervening years, Rathlin has flourished. “Its primary school has nine pupils, its highest number for years, and the previous year’s baby boom – five babies born – is unprecedented in living memory.”

Barkham is an informative and highly entertaining traveller but distilling the essence of what it means to be an islander is a difficult task. He finds there is a secrecy about island life. On St Martin’s in the Isles of Scilly, a resident tells him that it “doesn’t do to say what you shouldn’t be saying. It’s horrible if you fall out with someone.”

He approaches these islands as an outsider eager to discover their natural as well as social histories. He clearly delights in their flora and fauna, particularly the bird life. But he is also a shrewd observer who resists the idealised romanticism some visitors see in island life. Island communities have a more acute sense of their past, he realises, but they are looking to the future.