A vociferous "Brexiteer" and candidate for the leadership of the UK Conservative Party, and with that the role of Prime Minister herself only days ago, Leadsom will now oversee a department responsible for ensuring compliance with key European environmental legislation, including significant rules governing the waste and recycling industry.
A spokesman for Defra said: "The Queen has been pleased to approve the appointment of Andrea Leadsom MP as Secretary of State for Environment, Food and Rural Affairs".
She replaces Liz Truss, who had been Defra Secretary since July 2014 and who has now been appointed as Justice Secretary.
Andrea Leadsom has said that it would be "sensible" not to appoint a man to look after young children because he might be a paedophile. In an open letter to the new Prime Minister yesterday, the Food and Drink Federation (FDF) set out the sector's most pressing priorities for the negotiations with the EU on the UK's new relationship with the Union.
In 2007, Leadsom argued that "subsidies must be abolished" in an article on how to rejuvenate British farming.
Mrs Leadsom, 53, had served as a junior Minister of State for Energy at the Department of Energy and Climate Change since May 2015, but was promoted today after meeting Mrs May at 10 Downing Street at around 2.30pm. "There is much at stake and we count on Defra's support to foster growth and success in our great United Kingdom dairy industry", she commented.
Leadsom, a former banker and fund manager who served as energy minister in the previous government and campaigned for Britain to leave the European Union, recounted the episode to a parliamentary fracking group.