The most senior woman executive at BP has won a prestigious business award.

Vivienne Cox, aged 46, has held several top jobs with the oil giant and heads 7,500 staff across the world.

She also finds time to sail, swim, play squash and look after two young daughters.

Ms Cox beat four finalists - including Hilary Devey, the managing director of Leicestershirebased Pall-Ex - to win the coveted Veuve Clicquot Businesswoman of the Year Award.

Other finalists included Edwina Dunn, co-founder and chief executive of London-based marketing consultancy Dunnhumby and Emma Harrison, founder chairman of training firm A4e in Sheffield.

The award - considered as the 'Oscars' for female entrepreneurs - was presented to Ms Cox by Chancellor Gordon Brown at a ceremony last night at Claridge's in London.

Having grown up in Devon, Ms Cox read chemistry at the University of Oxford. She then joined BP Chemicals, selling chemicals to companies in Northern England.

She took a year out from BP to complete an MBA in France, before returning to the firm to set up a commodity derivatives group in oil trading, which became the number one foreign oil company in Russia.

Ms Cox ran BP's Rotterdam refinery, moved to Vienna to set up the firm's business in Central and Eastern Europe and then took on Air BP, the company's aircraft refuelling business.

She is now part of BP's senior leadership team, employed as executive vice president in charge of several areas, including the company's alternative energy business.

Ms Cox admitted that the oil industry attracted more men than women, but added that her gender had never been an issue in her career.

She said: "I have never felt disadvantaged in any way. In fact, working in an industry like this is a real opportunity for a woman because there are not many of us."

When asked about her management style, Ms Cox said: "I very much believe in getting the best out of people, but you have to trust them. My role is to provide them with clear boundaries and expectations, but give them space to get on with the job.

"My ambition has never been to aim for a particular position or place in a company. I am much more interested in where I can make a real difference."

Ms Cox is at her desk by 8am, having done an hour's work on her way to the office. She tries to leave by 5.30pm to spend time with her children, aged seven and two.

She advised girls considering a career path. "Really believe in yourself, because there is nothing a woman cannot do," she said.

Ms Cox said it was a "real honour" to win the award.

"I hope that the stories of all the past winners and those other businesswomen nominated, offer encouragement to women in business everywhere," she added.