Who are Nick Timothy and Fiona Hill - the PM's quitting advisers?

Theresa May's joint chiefs of staff have resigned following the Conservatives' disastrous General Election result.

As central coordinators of the Conservative manifesto and General Election campaign, Nick Timothy and Fiona Hill have attracted much of the blame for Mrs May's failure to win a majority of parliamentary seats.

Their departures from Downing Street came as Tory MPs demanded the Prime Minister to change her governing style in the wake of the election meltdown.

The Prime Minister has also been criticised for investing too much power in the pair, who were notorious in Westminster for fiercely guarding Mrs May.

But who are the duo, known as "NiFi" by some?

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Nick Timothy

The Birmingham-born son of a steel worker and school assistant, Mr Timothy is a passionate supporter of Aston Villa and a keen cricket fan.

Like Mrs May he attended a grammar school, where it is suggested he first developed his Conservative beliefs - having noticed that if Labour had won the 1992 election they intended to shut his school.

He then studied at Sheffield University, becoming the first member of his family to enter higher education, before entering politics.

Mr Timothy is described as "anti-Establishment" in his beliefs, with his political hero being the radical 19th century mayor of Birmingham Joseph Chamberlain - about whom he has written a short biography.

He worked as a Conservative researcher at the party's central office before becoming special adviser to Mrs May at the Home Office.

A row over his refusal, as a publicly funded employee, to campaign for the Conservatives at a by-election in 2014 saw him ousted from the Home Office amid tensions between Mrs May and David Cameron.

He was also barred from the Tories' candidates list for the 2015 General Election.

Mr Timothy went on to work for the New Schools Network, a charity promoting free schools, and voted to leave the EU in 2016.

He was appointed Mrs May's joint chief of staff in July 2016 after the Brexit vote led to her election as Tory leader and Prime Minister.

Martin Selmayr, the powerful chief of staff to European Commission President Jean-Claude Juncker, suggested the 37-year-old had been sacrificed by the Prime Minister so she can cling to power despite throwing away her House of Commons' majority.

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Fiona Hill

Unfairly or not, Ms Hill has become known as the Prime Minister's defender-in-chief.

The 43-year-old was born in Greenock, in the west of Scotland, and was state educated in Glasgow.

She entered journalism as the sole female football writer for the Daily Record, before moving on to The Scotsman where she once praised the power of kitten heels - a favourite of Mrs May - in an article.

Ms Hill entered TV journalism with Sky News and then moved to work for the Conservative press office while the party was in opposition.

After a brief interlude at the British Chambers of Commerce, she returned to work for the Tory party and soon became special adviser to Mrs May at the Home Office, where she teamed up with Mr Timothy.

Perhaps due to her own fondness for fashion, Ms Hill was often branded Mrs May's style adviser among her many other duties.

It is also said Mrs May's focus on tackling modern slavery at the Home Office was a result of Ms Hill.

Known by her married name of Fiona Cunningham at the time, Ms Hill was forced to resign from the Home Office in 2014 following a spectacular row with then education secretary Michael Gove over Islamic extremism in state schools.

Ms Hill was revealed to have been the source of briefing against Mrs May's Cabinet rival.

She went on to work for a lobbying firm before returning to Government - and having reverted to her birth name after a divorce - to link up with Mrs May and Mr Timothy again in Downing Street last summer.

Since that time, Ms Hill's reputation as a fierce protector of the Prime Minister grew, getting involved in a furious text exchange with Nicky Morgan after the senior Tory MP criticised Mrs May's £1,000 leather trousers.