Lingerie tycoon Michelle Mone has described criticism of her for using a taxpayer-funded chaffeur driven Government ministerial car as "unfair" because she is trying to "help other people achieve their dreams".
The founder of lingerie brand Ultimo, who is reportedly worth £20 million, is not a Government minister but is carrying out a Department for Work and Pensions review of small business support for people from less advantaged areas.
The 43-year-old faced criticism after appearing to boast about the car on social media.
But the entrepreneur later stressed that she is working unpaid for 50 days on the review and had only taken a short journey from her London home to Euston station.
She tweeted: "I'm working so hard&giving over 50 free days for this review to give back.I got a lift in a car for 15 mins,dropped at the train station...
"How is this fair when all I'm trying to do is help other people achieve their dreams? I will continue to work hard & carry on with my work".
Officials did not reveal the cost of the journey but claimed it was cheaper than flagging down a black cab and or even catching the Underground and then claiming the money back through expenses.
They said it was offered to the businesswoman because a minister was not using it at the time on Wednesday.
Mone, who was recently given a peerage by David Cameron, was travelling to Stockport to continue work on her review and in a tweet which has now been deleted but published by various news outlets she appeared to boast about using the car.
Alongside a photo of a Jaguar steering wheel and dashboard, she said: "The things you do..in Government car drying my travel top...love it so much. See you soon #Stockport #betheboss".
TaxPayers' Alliance political director Dia Chakravarty said: "Taxpayers will be furious that their hard-earned money is still funding luxury cars for our politicians.
"If a taxpayer-funded car is at all necessary to carry out official work there are much cheaper options available."
A DWP spokesman said a pool car arrangement was introduced in 2012 to reduce the overall running costs of ministerial travel.
He said the "the car was not required by a minister" and was "offered to Michelle Mone for use in connection with legitimate government business".
Mone co-founded Ultimo's "cleavage-enhancing" bras in 1996 with her then husband Michael.
The bras have often been promoted by celebrities, most famously by actress Julia Roberts who wore the firm's miracle solutions plunge bra in her Oscar-winning performance in Erin Brockovich.
Following a protracted divorce, her ex-husband left the company in 2013, and a year later Mone sold 80% of the business to Sri Lanka-based lingerie group MAS Holdings.
Mone has a high media profile and has appeared on TV shows as diverse as The Apprentice, Celebrity MasterChef and Surprise Surprise.
She also owns stakes in a tanning firm, a slimming business and works as a motivational speaker.