Belfast Film Festival screen Eric Marquis' rarely-seen and decidedly quaint film shot in Belfast and beyond in 1958

This film has buried cinematic treasure smeared over it, from the muddy print and the fact that it stops and starts every few minutes during this Belfast Film Festival screening, to the proud, somewhat ironic, trumpeting as an 'EJ Fancey Production'.

Even the company's logo marks Shamus as a treat from yesteryear – a slumped silver horse with wings: Pegasus with an inner ear problem. We're all set up for funny, fuzzy fabulousness and Shamus does not disappoint.

IMDb is tantalisingly spartan in its coverage of the film, with just the relase date listed (1958) and it's two stars: John Francis Rooney as Shamus and 'Tiny Littler' as Leprechaun. Neither actor ever appears in another film. Writer/director Eric Marquis doesn't fare much better. Despite having maintained a decade-long career in documentary film making, he is as shadowy and elusive as his cast.

Shamus starts, as it must, with a bus trip for the charges of the Ormeau Orphanage. Shamus, out in the wide world, wastes no time in marking his new territory up against a tree. Already we can see he isn't afraid to colour outside the lines – a quality that will stand him in good stead with what the next hour throws at him.

The orphan boy meets a tramp with the most extraordinary accent I've ever heard. (I can only assume that the film was made in Ulster and dubbed into 'Irish' by English actors at a later date – nobody's accent convince here, not even the English ones). The tramp mistakes him for a leprechaun and then has to explain what a leprechaun is.

No sooner does Shamus know about the little people than he overhears one loudly singing his job description while banging arrhythmically on a shoe. Shamus manhandles the little man with steely-eyed determination (you can tell this is one of the real fairy folk, as his lips magically don't synchronise with what he is saying).

Once his pot of gold has been found, Shamus legs it with a curse ringing in his ears: 'Until you find an Irish donkey, you'll remain a little monkey.' Shamus spontaneously grows a tail at this point and looks distinctly non-plussed, but is it really so bad? After all, tough guy Dempsey and Makepeace actor Michael Brandon was born with a tail and it didn't do him any harm.

Unaware of the exchange rate, Shamus is swiftly cheated out of a gold coin by a kindly old drunk, who grins gummily while toasting that his beer's 'back to pre-war strength' – a drink never tastes as good as when it is cheated from a child.

From here on in, Shamus becomes a Candide for our times, skidding from scrape to scrape: a kindly cafe proprietor named Guiseppe (accent as heroically wayward as any in the film) offers to cut off his tail with a carving knife; a startled physician accidentally poisons himself while searching for 'Nerve Tonic'. Shamus runs amok, dodging policemen and marauding street urchins; all the while his crock of gold remains unmolested.

There is some fantastic footage of a lost Belfast here: City Hall is unchanged (I don't notice whether the flag is flying) but the tenements and crowded shop fronts show a city teeming with life, bustling, archaic and odd.

The docks are alive and gloriously technicolor red against the dreary browns and greys of the rest of the film. This is the true value of features like this: in some ways (in lots of ways) the story is incidental – it's the accidents, the backgrounds, the attitudes of both the characters and the film makers that jar, that mark a difference between our cultural ideas.

There is, for instance, never any sense of jeopardy in this film. Shamus is a bullet proof little boy of the type that uniformly featured in fiction of this time. Nothing bad can happen to him. Stowing away on a boat to Liverpool, he is sold into child-slavery to a circus by a sailor who puts him in a sack, sets fire to him and seals the deal with the line 'Turn around and show the gentlemen your money making proposition.' This, I confidently suggest, is not a line you will hear in a modern children's film.

None of the above seems to upset the phlegmatic Shamus, though he is a little put out by the fire. He escapes the circus by turning their own flea circus on the carnies, and toddles off into a suspiciously rural Liverpool where everyone has a Home Counties accent.

He then saves a little girl from drowning, goes to live with her family, meets a talking donkey named O' Toole, gives his pot of gold away to the sick and the elderly and wins a donkey derby. His tail is magicked away and, as a nice little addendum, the little girl's father rings the orphanage and arranges to adopt him over the phone. Surprisingly little paperwork involved.

I don't feel bad about the spoilers in this review – realistically you will not to be able to see Shamus anyway. It's thanks to Creating Connections and the Belfast Film Festival that it is being seen at all. This film is a fascinating, evocative and bizarre postcard from another time, another world really. If we share anything at all with this foreign land, it is the universal truth that Leprechauns are cobblers.

Belfast Film Festival continues in venues across the city until April 5.