Therese Coffey MP, an environment minister and MP for Suffolk Coastal, has been promoted to Work and Pensions Secretary.
Elected in 2010, Ms Coffey is a former deputy Commons leader and was appointed as environment minister by Theresa May .
The Liverpool FC fan backed Remain during the EU referendum in 2016 and voted against legalising gay marriage in 2013.
She holds up former Tory leader Margaret Thatcher as her political hero.
Ms Coffey, who has a doctorate in chemistry, told Conservative Home in 2010: “She stood up for Britain, for enterprise and for freedom. Plus she is the only science graduate ever to have been PM.”
Her predecessor Ms Rudd resigned after suggesting the Government was aiming to take the UK out of the EU without a deal.
The Hastings & Rye MP said the PM failed to satisfy her that the Government was doing enough to negotiate an agreement with Brussels.
She said: “I have not seen enough work going into actually trying to get a deal.
“When I asked Number 10 for a summary of what the plan was for actually getting a deal, I was sent a one-page summary.”
Ms Coffey, an avid fan of Devon rock band Muse, comes to the Cabinet amid deep political turmoil with Downing Street at loggerheads with Parliament over the future on Brexit .
What is her voting record on benefits?
Ms Coffey is for the most part a loyal Conservative meaning she backed the bedroom tax, cutting ESA for the disabled by £30 a week and in favour of cutting Universal Credit benefits for those in work.
She voted for the Welfare Reform and Work Bill in 2015 which included reducing the household benefit cap, to freeze the rate of many working-age benefits and to reduce social rents in England.
This also contained measures to reduce the welfare cap, the two-child policy,and abolishing child poverty targets.
Her track record on welfare has already concerned campaigners.
Shadow welfare secretary Margaret Greenwood has argued that Ms Coffey’s “first act” as Work and Pensions Secretary should be to axe Universal Credit.
“Therese Coffey is now the fifth Secretary of State for Work and Pensions in the past three years,” the Labour MP said.
“At a time when Universal Credit is in crisis, the most vulnerable people in our society need dedication and stability, not more chaos.
“Universal Credit is clearly failing. In her first act as Secretary of State, Therese Coffey must stop the roll-out of Universal Credit as a matter of urgency before any more people are pushed into hardship.”
And on other issues?
Unlike her predecessor Amber Rudd, Ms Coffey is not taking on the role of minister for women and equalities probably due to her opposition to same-sex marriage.
She was one of 73 MPs who voted against extending equal marriage to Northern Ireland, in the absence of a devolved government in the region.
She also strongly opposed the introduction of same-sex marriage in England and Wales in 2013.
Ms Coffey was one of 15 MPs who publicly urged the House of Lords to block the legislation after it won overwhelming support in the Commons by a vote of 395-170.
In a letter to peers, Coffey urged them “in the strongest terms” to block the bill, claiming that the government was introducing same-sex marriage “without any mandate.”
She wrote: “None of us was elected on a platform to redefine marriage. Genuine concerns about the impact on society’s understanding of marriage and the Bill’s implications for free speech and civil liberty have been swept aside.”
The letter claimed: “Our postbags testify to the deep unpopularity of the Bill. Most of our constituents simply believe marriage is a unique institution that forms the bedrock of society and should be left as it is.”
She voted in favour of repealing the Human Rights Act, against greater gambling regulation and in favour of restricting legal aid.