Glossy and groomed, Katie Derham looks expensive. It’s tempting to say that she looks a million dollars, but that would be a bit of an exaggeration. To be precise she looks £50,000, exactly the value of the dress she is wearing today.

It’s made entirely of banknotes and pound coins pinned on to calico, and the reason she is surrounded by beefy security men. “It’s a bit itchy to wear, actually,” she says. There’s a sigh of relief when she changes into her nightly newsreading uniform, a smart grey pin-striped suit and a nononsense white shirt, though I notice she wears the gold stilettos just a bit longer than she needs to.

Derham loves glamming up. Blanketed with banknotes, she must have felt like the bride in My Big Fat Greek Wedding. The frock has been made to celebrate the culmination of a great British handout that Derham will present next month on ITV. The People’s £50m Lottery Giveaway – organised by the Big Lottery Fund, which distributes half of the good cause fund – will award the entire sum to the one heritage project deemed to be the most deserving.

The prize makes the million or so lottery sum awarded on BBC’s Restoration, the programme fronted by Griff Rhys Jones, seem paltry. “The £50m made me sit up,” says Derham. “The scale and scope of this contest attracted me to it. Everyone who entered is thinking very creatively and thinking big.” The prize purse is a television first – this amount has never before been decided by a public vote. “This is about people power and about the things that matter to us,” she adds. “It’s also about leaving a legacy for future generations.”

Once the project is completed, she adds, the face of Britain will have been changed irrevocably.

The show has been two years in the making. There were 33 entries, with Swindon’s Science Museum, for instance, vying for selection with Somerset’s waterways system. The four finalists include Cornwall’s Eden Project, Sherwood forest near Notting-ham and the Black Country urban park in the West Midlands. Another project, called Sustrans, aims to provide a network of cycle and walking routes across the country.

The Eden Project wants the money to build a new environmental complex while Sherwood forest’s backers aim to create a green lung in the heart of England, replanting the forest and encouraging tourism. Meanwhile, advocates of the Black Country park want to clean up canals and restore the birthplace of Britain’s industrial revolution.

As Derham observes, each is a grand scheme with the grandest of intentions. To help woo the public each finalist has its own celebrity champion. Sherwood has the actor Brian Blessed, Eden has Ray Mears, the survival expert, the Black Country has the actress and singer Toyah Will-cox, and Sustrans has the presenter Lorraine Kelly.

Derham hopes the programmes, to be screened nightly over five evenings before the phone lines open for voting, will stimulate a national debate. Perhaps it will become the stuff of dingdongs at dinner parties. “I’d like to think it will get people talking about what matters, about what our generation wants to be remembered for,” she says. “The Victorians gave us great public buildings, libraries and town halls and railways, but what will we leave behind?”

The series may catch on in the way that BBC2’s Great Britons did five years ago. Then viewers heard Jeremy Clarkson arguing the case for Isambard Kingdom Brunel; the journalist and broadcaster Andrew Marr for Charles Darwin and the comedian Alan Davies for John Lennon. But it was the late politician Mo Mowlam, championing Sir Winston Churchill, who won the day. Everyone involved with the £50m giveaway hopes people will keep the phone lines buzzing.

Ouch. Bit of a sore subject with ITV. It has been at the centre of a scandal, described as one of the biggest frauds in television history, since it was exposed earlier this year as having cheated the public with its premium rate phone lines.

All calls were suspended to many programmes after revelations that viewers had been tricked into calling premium lines when voting had closed. Ofcom, the television watchdog, fined GMTV £2m in September, saying it had been guilty of “widespread and systematic deception of millions of viewers”. The Serious Fraud Office has asked Ofcom for further details and is considering an investigation.

Derham acknowledges the problem. “Yes. I can assure you that unbelievable care will be taken that there are no mistakes on this one,” she says. “There will be nothing unethical, no profit will be made and that will be made crystal clear to viewers. There are no more second chances on air and no one wants to do any more apologising.”

Calls will be charged at the national rate and the organisers have asked the independent body Electoral Reform Services to oversee the process.

No wonder ITV turned to Derham, the squeaky-clean newsreader who co-presents the lunchtime news with Alastair Stewart.

Derham, 37, is married to John Vincent, who works in the restaurant business, and has two daughters. She comes from a comfortable middle-class home in Cheshire and was privately educated. As a child she wore thick glasses and braces and was nicknamed “girder gob” by her brothers.

Her father (a chemist) and her mother (a French teacher) were delighted when she became the first person in her family to go to Cambridge, where she read economics. She says her parents set high standards but weren’t pushy. She has studied both piano and violin to grade 8 and now hosts a show on Classic FM.

She would love “to do a Jamie Oliver”, she says, in schools by introducing music lessons for all. “There are pockets of excellence but the basic level of music teaching in most schools is poor,” she says. “It’s a damn shame. Where are our future musicians going to come from?”

The only other time she loses her cool is on the thorny old subject of female newscasters and their looks. Are she and her ilk just television totty, mere Autocuties? Kate Adie once famously dismissed many of them as having “cute faces, cute bottoms and nothing in between”.

Derham sighs. “There is never any let up in attention paid to female newscasters. We all know our journalistic credentials are sound and we’ve had to develop a thick skin. I can cope with it.” So bring it on. Girder gob or glamourpuss, Derham can take it.

The People’s £50m Lottery Giveaway starts on ITV on December 3. For more details see www.peoples50million. org.uk

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