There are now just two candidates in the race to be the country's next prime minister.
But where do Theresa May and Andrea Leadsom stand on some key issues?
- Brexit negotiations
May and Leadsom supported opposing camps in the run up to the EU referendum and stand divided over issues surrounding Brexit.
May: Campaigned to stay in EU but following the Brexit vote said that she will unite the party. She said the priority in negotiations is to allow British companies to trade with the single market. She has argued that the UK must be clear about its negotiating position before triggering Article 50, saying that she would not invoke it this year.
Leadsom: The Brexit supporter has said that "no one needs to fear our decision to leave the EU" and promised to find a "third way" by continuing free trade whilst controlling immigration. She said Article 50 should be triggered immediately before conceding that negotiations should take place first.
Leadsom: Said during the referendum campaign that EU migration would "overwhelm" the UK and was critical of east European immigration in particular. Following the vote for Brexit, she has committed to allowing EU nationals already living in Britain to stay saying they should not be used as "bargaining chips".
May: Was criticised for not guaranteeing that EU nationals already living in Britain can stay. She has promised to seek action on free movement but admits leaving the EU will not immediately stem the flow of migration from Europe.
- The economy
Leadsom: Promised "prosperity not austerity" and said she expected to see "continued growth" in post-Brexit figures. She has signalled to keep up the Leave campaign's momentum to focus on boosting the incomes of so-called "left behind" voters focusing on tax cuts for the low paid and "supercharging" the "northern powerhouse" project.
May: Said she will not hold an emergency budget in response to Brexit and discussed reforming capitalism calling for a small but strong state. She promised to tackle "gross abuses of power" and address the gap between the generations.
- Social policy
May: Has promised a one-nation Conservative "radical programme of social reform" to help those from "ordinary, working class families".
Leadsom: Says she will appoint a key housing minister with a bigger budget who will be in post for the long term.
- Foreign policy
Leadsom: Voted for intervention in Syria in 2013 and to join airstrikes against ISIS last year.
May: As Home Secretary, she has tackled issues associated with terrorism abroad. May voted for the Iraq war when she was an opposition MP and has consistently voted for intervention in Syria.
May: Expressed concern over the expansion of Heathrow airport but said that the HS2 rail project will boost the UK's economic growth.
Leadsom: Sceptical over HS2 saying it may not be good value for money but has not made up her mind on Heathrow.
- Gay marriage
May: Voted for gay marriage in the UK in 2013, which came into force the following year.
Leadsom: Abstained from the vote and has said she "didn't like" the legislation because of "hurt caused to many Christians."
- Fox Hunting
This is one issue that both candidates agree on. They are both pro fox hunting.
Leadsom: Calls foxes "vermin" and wants to repeal the ban.
May: Once famously argued with astronomer Patrick Moore on live TV over her call to scrap the ban.