Class act: The amateur-dramatics societies that could give the pros a run for their money

Ah, the smell of the greasepaint, the roar of the crowd… or should that be the whiff of damp community halls and the shuffle of family members with a sense of duty?

Amateur dramatics doesn't always enjoy a good rep. Stereotypes abound: of megalomaniac directors, would-be divas with swollen egos, affairs igniting in the wings, mildewed costumes, and toppling plywood sets matched by acting skills even more wooden and one-dimensional. Such is the enduring nature of these tropes that Alan Ayckbourn's 1984 play A Chorus of Disapproval – a supposedly affectionate send-up of local am-dram – is currently enjoying a West End revival

All of which would be met by howls of dissent from the thousands of people across the country who take part in community theatre. There are more than 2,500 such groups in the UK, putting on a staggering 30,000 productions every year. That's no niche interest; that's a huge swell of creative endeavour, important to people from all walks of life.

Certainly, that was my own experience of community theatre. Growing up in mid-Wales, making your own entertainment was pretty much a necessity, and I threw myself into everything from wild reinventions of Shakespeare with the local youth theatre, to a community production of Under Milk Wood (a predictably popular choice in small-town Wales), which had such a large cast it's a wonder there was any community left to watch it. Sure, there were directors who swore through their roll-up cigarettes, there was gossiping backstage and tantrums over plum roles, and not everyone – I hold my hands up – was especially gifted at acting. But there was also passion, commitment, fun, friendship, the thrill of performing. And there were actually some very good shows, with real ambition.

That's not just a nostalgic view; it's what you'll hear if you talk to enthusiasts up and down the country, and it's also what you'll see if you tune in to a new show on Sky Arts: Nation's Best Am-Dram takes its form from the classic TV competition format – there are tears, naturally – but they've uncovered true talent. Eight troupes were judged by actress Miriam Margolyes, producer Bill Kenwright and critic Quentin Letts, with the winning group getting to perform for one night in London's West End.

The series is explicit in its celebration of the high calibre of some amateur groups. And all three judges were impressed by what they saw – although, entertainingly, they didn't always see eye to eye. "Criticism is a highly subjective response," suggests Letts. "Sometimes I was wowed by an individual's performance. Sometimes I was won over by the consistency of a company's acting or the director's interpretation. But there were three of us in the judging room, all opinionated, all bossy!"

Those who took part in the competition are pretty opinionated too, and one thing none of them likes is the title: the phrase "am-dram" is not popular (the series was originally called Stagestruck). Anne McIntyre, director of the Crossmichael Drama Club, Galloway, says, "People tend to pooh-pooh amateur dramatics. Even the name; people think: 'Am-dram – rubbish'."

Tony Gibbs, chief executive of umbrella organisation the National Operatic and Dramatic Association, agrees. "I have to say [the name is] dreadful. Amateur theatre still has to overcome a lot of stereotypes. 'Am-dram' tends to be shorthand for poor quality, which is very unfair." While Gibbs acknowledges that standards vary – from enthusiastic hobbyists to shows with six-figure budgets – he adds that, "What we need to do is recognise that amateur theatre, in all its guises, is already at the heart of the community arts scene. Especially in rural parts of Britain, where amateur theatre is theatre."

Carole Williams, from the Scottish Community Drama Association, echoes this stress on localism, pointing out that professional companies aren't going to reach the most remote areas. "Inevitably it's really hard for people across Scotland to access theatre – they may not have anything nearby. The other thing I've learnt is that people are very loyal: they like that they go along and recognise the people on stage. They just really support their local groups. In the central belt [of Scotland], it's more ambitious. "

Scotland is well represented in Sky's competition, with three groups from north of the border. And the Glasgow company Strathclyde Theatre Group (STG) certainly fits Williams' "ambitious" tag. It's been going 40 years, staging up to 12 shows a year; currently it has an active core of 50 members – and a further 200 people on the periphery. So far in 2012 it has tackled The Glass Menagerie, Abigail's Party and Coriolanus; when I visit, the group is preparing a double-bill of Arthur Miller, All My Sons and Death of a Salesman.

Sadly, STG lost its home last year – it had a proper theatre, the Ramshorn, but a long association with its owners Strathclyde University has come to an end. The company is still able to use uni rooms to rehearse in, though, so with a leap of imagination, a neon-lit seminar room becomes a stage. If anyone was attracted to am-dram for the glam, this wouldn't fit the bill.

But the players will not be put off by being made homeless. STG's mantra is "working to professional standards", and watching the group dissect Miller, delving into character history and power dynamics, they clearly take it very seriously. Not that there isn't plenty of joking among the cast, but when in role, focus is total.

At the helm is Bruce Downie, dressed head-to-toe in regulation director black. An STG vet, he's been directing since 1999. "Over the years we have been very ambitious, we've been able to do productions professional companies couldn't even consider because of the number of people in them. We've probably done more Shakespeares than any other company in Glasgow in recent memory," he says.

For actors, putting on a show is a commitment, with rehearsals a few evenings a week; for a director, it's a mammoth task, which sees them holing up in little, airless rooms, night after night, not to mention also having to deal with the set, lighting, costumes, props, publicity. So why put yourself through it? "It certainly occupies an enormous amount of my time," Downie acknowledges. But, he adds, "I love the buzz of pulling a show together, the opportunity for creativity."

Two of the stars of Death of a Salesman, Alessandro Conetta (playing Biff) and Mark Coleman (Willy Loman), are of the same mind. Both tried their hand at professional acting, but now have STG as their creative outlet. "I work all day; I'm here till 10 o'clock then I'm up at six in the morning," says Conetta, whose day job is delivering produce to Glasgow's Italian restaurants. "Why do I do it? Because I love it! I don't think there's a bigger rush than being on stage." Coleman, a drama teacher and, as a member for 19 years, now the chair of group, says it's about "the thrill of surprising people with how good it can be, and making professionals a little bit jealous, actually".

Another drama-school-grad-turned-teacher, Rob Walker, is a member of Regent Rep, from the small town of Christchurch, near Bournemouth. "I personally have a need to express myself," he explains – but he also values the social aspect. "There's a lovely community spirit; you get a sense of belonging. I really don't come across many people who fit the stereotype of little petty egos. I [hope] the [Sky] shows will challenge those preconceptions."

Anne McIntyre knows all about community spirit. She was "kind of flung into [directing] because nobody else would do it" – and stopping the Crossmichael Drama Club, which had been going since 1941, was not an option. "In rural areas, there's not much else to do except sheep and cows," she jokes. Although it has only 10 members – losing young people to university is a problem – some actors are second- or third-generation. "There's at least two or three that it's in the family history, quite a few farmers, it's a right band of people," she says. "You have to be slightly mad to do it – and you have to have dedication. It's the people who are willing to give four nights a week and build sets in a draughty shed in midwinter who really keep it going."

So maybe community theatre isn't all encores and roses. All the people I speak to are wary of financial pressures, be that the rising costs of venue hire or having to sacrifice lofty artistic aims to ensure you get bums on seats. But for those who take part, the sheer joy is undeniable.

"It's like people doing extreme sports – going on stage, you get a buzz," says McIntyre. Quentin Letts got involved with Nation's Best Am-Dram because he wanted to reconnect with that "raw excitement" of performance – and he got it by the bucketful: "The backstage adrenalin was as strong as street vodka, and afterwards the players' eyes glinted manically," he says. So perhaps it should be no surprise that while only a few people ever get a shot at making it on the professional stage, there's still huge appetite among amateurs for a shot of that performance high.

'Nation's Best Am-Dram' begins on Sky Arts on Wednesday; the STG performs its Arthur Miller double-bill at Cottiers Theatre, Glasgow, from Tuesday to 24 November; 'A Chorus of Disapproval' is at the Harold Pinter Theatre, London SW1, to 5 January