She has only been elected to the British parliament six years ago and has never served in the Cabinet.
But Energy and Climate Change Minister Andrea Leadsom has soared to political prominence after campaigning for Britain's exit from the European Union (Brexit), and is now one of two candidates of the Conservative Party who are contesting to succeed Prime Minister David Cameron.
In a ballot among 330 Tory Members of Parliament, the 53-year-old received 84 votes, trailing behind Home Secretary Theresa May who garnered 199 votes.
Here's what you should know about Mrs Leadsom:
1. She came from humble beginnings for a Conservative politician.
She was brought up in Tring, Hertfordshire, by a divorced mother in a terraced house with an outside toilet. After attending Tonbridge Girls Grammar School in Kent, she went on to read political science at Warwick University.
2. She worked in the banking and financial industry for 25 years before becoming a legislator in 2010.
She was deputy financial institutions director at Barclays Bank and according to her website, worked with then Bank of England Governor Eddie George to avert a crisis after the 1995 Barings collapse. She also worked as Head of Corporate Governance and Senior Investment Officer at Invesco Perpetual, one of Britain's largest retail fund managers.
3. Mrs Leadsom entered Parliament in 2010.
She was the Member of Parliament for South Northamptonshire. In doing so, she realised an ambition she first developed at the age of 13. Since then, she has only held positions as economic secretary to the Treasury and now energy and climate change minister - both junior positions.
4. Critics have accused her of inflating her experience in the banking and financial industry.
Those who worked with her have told British news media that she exaggerated her role at Barclays Bank and Invesco Perpetual. But she told Sky News: "My CV is correct." She has also defended her lack of frontline political experience, saying she has had two years of running a ministerial portfolio and has also run businesses and charities. "Our current prime minister hadn't been in government at all before he became leader and then prime minister," she said.
5. She has laid claim to inheriting Mrs Margaret Thatcher's mantle.
She told the Telegraph in a recent interview that Britain's first female Prime Minister was "always kind and courteous and as a leader she was steely and determined. I think that's an ideal combination - and I do like to think that's where I am."
6. She had campaigned to leave the EU and is running as the candidate who will fully deliver Brexit.
She has said she would move quickly to trigger Article 50 of the Lisbon Treaty, the mechanism by which countries can leave the EU. She has also said that EU nationals should not be used as "bargaining chips" and should be allowed to stay in Britain post-Brexit.
7. Ms Leadsom has been criticised for her stance on gay marriage.
A Christian, she has said that she "does not like" gay marriage. "This is not about do I consider gay couples to be any less worthy of marriage than heterosexual couples - not at all, it's exactly the same. The issue is one I have around the consequences, the very clear hurt caused to many Christians who felt that marriage in the Church could only be between a man and a woman,'' she said.
8. She founded the Northamptonshire Parent Infant Partnership (ORPIP).
The charity promotes parent infant psychotherapy, based on her belief that strong bonds between parents and children in their early years can prevent anti-social behaviour and end the "cycle of misery passed down the generations".
9. Mrs Leadsom is facing demands to give a complete account of her tax affairs
This includes her family's use of trusts and bank loans raised via a tax haven.She and her husband Benjamin set up Bandal, a buy-to-let company, in 2003 to invest in more than £1 million (S$1.75 million) worth of properties in Oxford and Surrey. Documents seen by The Independent indicated that in 2004, the company raised loans from Kleinwort Benson (Channel Islands) Ltd, based in Jersey, a tax haven. In 2005, 24 per cent of the shares were transferred to two trusts set up for the benefit of the couple's children, as a way of avoiding inheritance tax.
10. She and her husband have two sons and one daughter.
SOURCE: BBC, THE GUARDIAN, THE TIMES, THE INDEPENDENT, THE TELEGRAPH