Unless you’re a fiftysomething aficionado of the 1970s West Midlands punk and post-punk music scene, the name The Nightingales probably means nothing to you.

Stewart Lee’s film is an obvious attempt to address that, bringing the band – who are still going – to greater attention. But more than that, it’s a celebration of any artist who perseveres ‘in the face of commercial and critical indifference’, as well as a love letter to the vibrant underground cultures of the 1970s and 1980s that fostered so much creativity.

By way of metaphor, the comic, sometime rock critic and ardent Nightingales fan tells the parallel story of King Kong, a sculpture of the movie ape commissioned for the centre of Birmingham in 1972 from the artist Nicholas Munro. But, rejected by the cityfolk, it was instead used as an advertising gimmick for a used car showroom before winding up dumped in a car park in Cumbria. ‘Birmingham has a way of rejecting its culture,’ Lee asserts at the start of the film, wondering if giant fibreglass effigies, or cult indie bands, will ever get the recognition they deserve.

It’s easy to see what drew Lee – a comedian whose long been suspicious of commercial success – to the story of Robert Lloyd, the frontman of The Nightingales and, before that, the Prefects. ‘We live in a culture where mediocrity is rewarded and originality and integrity are punished,’ Lee says.

Lloyd’s lack of mainstream success, despite some close encounters, is something of a running joke, even for the musician himself, who concedes his career was ‘fast-tracked into disillusionment’. After The Clash’s manager Bernie Rose called The Prefects  ‘amateur wankers’, the band used the insult as an album title, and there’s a hilarious appearance on daytime TV show Pebble Mill that baffles the presenters. Even the stone circle Lee and Lloyd visit is a disappointment, another metaphor.

Much of their conversations, however, happen in the pub, affectionate and amusing chats about the good old days over a pint. Those who only know Lee for his stern stage persona, will see a different side: engaged, enthusiastic, laughing.  Their chats occasionally tilt towards the self-indulgent, but for the most part  they, and the rest of the film, finds appeal beyond its core audience of middle-aged alternative rock fans.

Yet it’s also hard not to feel we have lost something from the days when you’d discover music from flicking through racks of vinyl in record stores or seeing bands in grungy dives such as Barbarella’s – the Birmingham venue where Lloyd first started, and, since it’s since been built over by a gleaming bank, represented here by a wheely bin.

That scene typical of the underplayed, offbeat humour you might expect from Lee, successfully brought out by director Michael Cumming, whose other credits include Brass Eye and Toast of London. Likewise, how many documentaries have ever asked Robin Askwith, erstwhile star of softcore sex comedies such as Confessions Of A Window Cleaner, to list all the people he ever showed with, as he sits in his home in Gozo, Malta?

Lloyd apparently resides at the overlap between Askwith, The Ramones and Frank Skinner – who, pre-comedy, auditioned for Lloyd’s band by singing the punk classic Blitzkrieg Bop in the street. Lloyd is clearly something of a polymath, too, having been a horse-racing pundit, restaurant critic (ousting Nigel Slater from a job) and even part of a sitcom writing team.  Here, comics including  Kevin Eldon, Bridget Christie and Nish Kumar recreate a scene from that show, Normal, commissioned as a BBC Two pilot but stymied by infighting among its creators.

King Rocker portrays Lloyd as rather a heroic figure for ploughing his own furrow (‘you’re too good for it to be a joke’, Lee tells him. And although as it documents his fallow years, drifting through London and working as a postman, the film’s tone is not to lament his lack of success, rather to celebrate the fact he’s mostly had an enduring career doing what he wants.

His story brings to mind other cult figures of his generation – Frank Sidebottom creator Chris Sievey, especially  – but also raises the question of whether such artists could emerge today, where few can exist in the gulf between making passion projects for the internet for no income, and the riches of superstardom.

And did the King Kong sculpture ever get the love it deserved? You’ll have to watch this charming, amusing and creatively inspiring documentary to find out.

• King Rocker premieres on Sky Arts at 9pm tomorrow.