Leave-supporting Stephen Barclay has been promoted to Brexit Secretary from his ministerial role in the department of health.
The relatively unknown politician, who is the MP for North East Cambridgeshire, replaces Dominic Raab.
Mr Raab dramatically resigned from the cabinet on Thursday over the draft Brexit withdrawal agreement.
Esther McVey also quit the cabinet alongside five other ministerial resignations over the proposed deal on Thursday.
— UK Prime Minister (@10DowningStreet) November 16, 2018
Mr Barclay will be taking on a stripped-down version of the role, limited to the domestic delivery of the withdrawal, preparations for different Brexit scenarios and passing legislation.
Prime Minister Theresa May will be taking sole control of the negotiations with Europe.
In a brief blog post on Mr Barclay's website from March this year, he wrote: "Jeremy Corbyn recently confirmed that Labour are taking a position that will mean the UK cannot have an independent trade policy after Brexit.
This means that under Labour we would be unable to sign our own trade deals around the globe."
He went on: "Brexit is a defining moment in the history of our nation. We will be forging an ambitious new partnership with Europe and charting our own way in the world to become a truly global, free-trading nation."
Mr Barclay is Britain's third Brexit secretary.
David Davis held the role between July 2016 and July 2018. When he quit he said it looked "less and less likely" the party would deliver on the Brexit result".
Mr Davis was followed by Mr Raab, who quit after just over four months in the role.
Mr Barclay was appointed as minister of department of health and social care on 9 January 2018. He was previously economic secretary to the treasury from June 2017 to January 2018.
From 2010 to 2014, he served on the public accounts committee and served as assistant government whip from May 2015 until July 2016.
Mr Barclay lives with his wife and two children in Wisbech, Cambridgeshire. He qualified as a solicitor in 1998.
Before entering politics, he worked as an insurance company lawyer for Axa Insurance, as a regulator for the Financial Services Authority, and as director of regulatory affairs and then head of anti-money laundering and sanctions at Barclays Retail Bank.
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Mr Barclay's promotion came as former home secretary Amber Rudd was named the new work and pensions secretary.
Mrs Rudd had been forced to step down seven months ago after she admitted "inadvertently misleading" Parliament over targets for removing illegal immigrants.