Neil Norman: Brand Spall is as enduring as its royal fan

No wonder the Queen follows Everyman Tim

He may not have been the most convincing Winston Churchill the cinema has seen, but Timothy Spall, who wobbled his prime-ministerial jowls in The King's Speech, remains one of our most treasured actors. Now comes the revelation that the Queen has put in a request to the BBC to send her DVDs of his video-journey, Timothy Spall: Somewhere At Sea, in which the actor and his wife, Shane, navigate their way from Fowey, in Cornwall, to West Wales on a Dutch barge. It seems that his fanbase is complete.

Turn on the television any hour of the day and you will hear Spall's phlegmy, south London accent promoting a British energy company or a chain of DIY stores ("It's got our name on it") in every commercial break. It is the warm and comforting tone of a lovable, if slightly roguish, uncle. Would you buy decking from this man? Absolutely.

And thus it is with his film performances, from the over-reaching chef Aubrey of Mike Leigh's improvisational Life is Sweet (liver in lager, anyone?) to the well-meaning wedding photographer in the same director's Secrets and Lies. Such is his ability that, in Albert Pierrepoint, he even managed to make Britain's last hangman seem like a genuinely caring human being.

But Spall is not only a reliable actor. In person, he comes across as a thoroughly reliable and endearing bloke and a fundamentally decent human being. What cements the attraction, however, and is probably why Her Majesty has enjoyed and wishes to continue to enjoy his misadventures on a Dutch barge – is his unwavering honesty and good humour. He is, in short, a jolly good egg.

Spall has the kind of physiognomy in which the male viewer can invest much of himself without fear. The large, slack-jowelled face not overburdened with a chin, the vague quiff of blonde hair, the dodgy teeth and the kind eyes act as a smokescreen to his real persona, which is erudite, observant and quick of wit. He can play gormless fat boys like Barry in Auf Wiedersehen, Pet and cowardly villains like the slippery, verminous Peter "Wormtail" Pettigrew in the Harry Potter films or Fagin in the 2007 television adaptation of Oliver Twist.

By consistent hard work in television, on film and in the theatre, Spall has become one of those rare creatures – a chameleon character actor of distinction (he was created OBE in 2000) and an easily recognisable personality who seems part of the nation's furniture.

But the most likely reason for Spall's embedding in our consciousness is his utter lack of snobbery and his embrace of his roots. Of all the actors I have encountered, he is the least hypocritical. An authentic Lavender Hillbilly, he was born in Battersea, south-west London. His father was a scaffolder before becoming a postal worker and his mother worked in a chip shop and later, self-taught, became a hairdresser.

Unlike many who have advanced well in their careers, Spall has kept faith with his roots and continues to live with Shane in south London in the yet-to-be-gentrified suburb of Forest Hill, where he raised three children, Pascale, Rafe – himself now an actor, much in demand – and Mercedes. The names provide a clue to the extent of his literary tastes.

While Spall's Everyman qualities go some way to explaining his popularity, it is the cocktail of mischief and honesty, anxiety and courage, vulnerability and stoicism that are so vividly illustrated during his round-Britain sea journey that have imprinted him on his audience. Now that this has been extended to include a request amounting to a royal warrant, it is clear that whatever he does, it will continue to be popular – as long as it's got his name on it.