Can Susan Boyle be the saviour of ITV?

When Susan Boyle walked out on to the audition stage during the first episode of the new series of Britain's Got Talent last Saturday, I Dreamed a Dream seemed an apt song for her to sing. Few songs tug the heartstrings as dolefully. "I dreamed a dream in time gone by, when hope was high and life worth living," it starts off, before telling a tale of love lost and hope extinguished: "But there are dreams that cannot be, and there are storms we cannot weather."

Boyle is 47, unemployed, perpetually single and lives alone with her cat, Pebbles, in Bathgate, West Lothian – a town apparently dubbed "a dump" by Britain's Got Talent judge Piers Morgan. Boyle's sunny (if gauche) demeanour masks a sad life: the youngest of nine, she was deprived of oxygen at birth, which led to learning difficulties and, as a result, a childhood marred by bullying. Forty years later, it was her mother – whom she lived with and cared for – who wanted her to audition for the ITV talent show. But she died in 2007, leaving Boyle suffering from depression and anxiety.

Simon Cowell was at his sneering best. Which singer would you like to be as successful as, he asked, before Boyle started her audition. "Elaine Paige?" she ventured brightly but uncertainly. Girls in the audience sniggered and there was a snort of barely concealed derision from Morgan.

Everyone concluded that this podgy woman with a frumpy frock, a wiry hairdo and heavy brows fell into the comedy-audition category. They settled into their seats for a good laugh, knowing she would massacre the song from, as she put it, "Les Miserabs". But then Susan Boyle started to sing.

And – like Judith Keppel winning £1 million on Who Wants to Be a Millionaire? or Paul Potts's rendition of Nessun Dorma on BGT two years ago – there followed one of those transcendent moments that make TV history. Boyle's voice rose pure and clear over the huge Glasgow theatre. Before even the first refrain, the sniggers had turned to applause.

When Boyle nailed the big rising note in the middle of the song, the audience were on their feet, cheering. Ant and Dec were screaming her on from the wings, and both Morgan and fellow judge Amanda Holden had welled up. Even Cowell couldn't stop his eyebrows rising in surprise. Boyle finished triumphantly – but fighting to be heard over the standing ovation – "Now life has killed the dream I dreamed."

Ironically, it was at that moment that Boyle's dreams – long since surely pronounced dead on her bleak council estate – were brought back to life. She was, said Morgan, the biggest surprise in three series of BGT auditions. She will contest the live semi-finals of the show in June, and is the 1/2 favourite to win the £100,000 prize. Cowell has begun discussions to sign her to his record label; meanwhile, Holden has vowed not to let him "spoil" her by "turning her into a glamourpuss".

At the time of writing, Boyle's performance has been viewed nearly 30 million times on YouTube. It's been on the NBC Today Show, covered in the Washington Post and Twittered about by Demi Moore. Boyle was interviewed on US breakfast show Good Morning America last Thursday, and has been invited to appear on The Oprah Winfrey Show.

More importantly for ITV – which, remember, foots the eye-watering bill of nearly £1 million an hour to make BGT – Boyle's performance was seen by more than 10 million people on ITV1 last Saturday. That's nearly half of the people who were watching television at that time in the whole country. Many of them will have tuned in feeling glum – their jobs lost or in danger, their houses devalued, their children's futures already mortgaged by Labour.

Indeed, this BGT episode scored ratings 17 per cent higher than last year's series opener, which perhaps reflects the fact that Brits generally have less money to spend going out on a Saturday night than they did 12 months ago.

When Boyle sang, my guess is that most of those viewers – and that includes the men – will have been moved to tears. By the time the 90-minute show finished, though – with contestant Fabia Cerra waggling her electronically obscured breasts in a comic striptease routine – almost all of them will have been much cheered.

This is a digital age, and superfast broadband, Wiis and iPhone applications may be gradually winning the war for the country's eyeballs. But even today, it remains true that only superannuated television channels such as ITV1 have the power to sit the nation on its collective sofa and, using the magic of telly, lift us as one from our slump.

The importance of TV talent shows is not entirely lost on the Prime Minister, who wrote letters of encouragement to last year's X Factor finalists and recently invited Simon Cowell to dinner. (Cowell, who is nobody's fool, wisely co-opted Morgan and Holden to come along and keep him company.)

ITV's future, however, seems to be of little consequence to Brown or his henchmen. Communications minister Stephen Carter will publish his Digital Britain report by the end of June, and (among many other things) it will pronounce on the future of broadcasting policy. It will determine the fate of Channel 4, whose bleats for public money would make a rather less appealing BGT audition. Channel 4 may have to shrink, and make fewer obscure documentaries. But it still sits on a £200 million-plus pile of cash, and is in no danger of disappearing.

The report is unlikely, however, to offer much relief to ITV. With a mountain of debt and falling revenues, ITV plc is in deep trouble. Its eventual insolvency is not out of the question. ITV1's historic position as our third television channel has long since ceased to be the fabled "licence to print money", yet it still labours under a unique (and uniquely onerous) regulatory regime that dictates how many ads it may show, how much it may charge for them, how much regional news it must offer and even where in the country it must make its programmes.

Culture secretary Andy Burnham recently decreed that paid "product placement" would continue to be banned on British television – a decision lamented by ITV, which is scrapping for any new revenue it can find. The Government and its media regulator, Ofcom, have resolutely refused to acknowledge the depth of the crisis facing ITV, the speed and scope of the regulatory relief that is required, and the potential consequences for Britain's television viewers – who also, by the way, are its voters – if the channel falters.

Among all its tatty factual shows and failed formats, the glory of ITV lies in shows such as Britain's Got Talent. Along with massive sporting fixtures, royal events and perhaps general elections, they are the only things now that bring the country together. Although Gordon Brown's dour world view would never acknowledge it, 10 million Brits feeling good about the same thing at the same time is priceless – even if it is something as trivial and transitory as a middle-aged Scottish lady singing a torch song.

The dream of mass-market television could well be a thing of our analogue past. But, as Susan Boyle and the poignant lyrics she sang have shown, some dreams can come back from the dead.

The question now is whether, as with so many other national assets, our Prime Minister is determined to behave like the grim reaper.