Victoria Clarke and her husband Nigel, who co-run Clarke and Tholomew Ltd, are now hoping to scoop the top title and a cheque for £50,000, courtesy of HSBC.

The national contest, in its eighth year, aims to seek out the most promising start-up businesses in the UK.

After 30 years selling advertising space, including 23 years selling airtime at radio stations all over the country, Victoria spotted a gap in a very crowded market that could help her realise a life-long dream of starting her own business.

Her idea was to offer clients "sight and sound" advertisements which run on billboards and on the radio – simple, but very effective.

"We are absolutely delighted to reach the regional finals," said Victoria. "I'm still in shock. To think that 18 months ago I was sitting in my conservatory, and now I'm in offices in Hampton – it's great.

"I was born in Peterborough, my dad worked in the brick pits, and for my company to be shortlisted for something like this is just amazing.

"It goes to show that if you really believe in what you're doing and are passionate about what you do, you can succeed."

Clarke and Tholomew's clients include Serpentine Green and Diligenta.

And Victoria is confident that it won't be long before the company reaches the magic £1 million turnover mark, which will then pave the way for future growth, including offices in other major cities around the UK.

The overall winner will be revealed at a black-tie gala dinner at London's Dorchester Hotel on October 29.

HSBC's head of business banking Huw Morgan said: "Last year, HSBC alone helped nearly 130,000 new ventures get off the ground, and this is representative of the entrepreneurial talent that exists in Britain today.

"Many are still only small businesses, but with big ideas. We are proud Start-Up Stars can contribute to their aspirations, and that the awards play a pivotal role in identifying the business leaders of the future."