Rory Stewart: Who is the outsider rising through the Tory ranks in the race to be PM?

Rory Stewart will likely have a taxi waiting for him outside the Palace of Westminster when the results of the latest ballot of Tory MPs is announced on Tuesday night.

It will be ready to take him home to his wife, Shoshana, and his two young children, after he is dumped from the Conservative leadership race following a spirited but ultimately unrealistic campaign to become the next prime minister. It would be an outcome that most observers expected when the contest begun last month, and one that many still think is the most likely conclusion.

But there will be another address programmed into the driver's sat nav on Tuesday: that of a BBC studio not far from Westminster, where, if all goes to plan for Stewart, he will rush after the announcement. There, he will go head-to-head with Boris Johnson, the frontrunner who he has spent weeks attacking, in a televised debate between the remaining candidates, and the tantalising prospect of a run-off between the two men will be rapidly increased.

It would be a remarkable outcome, given the newly-appointed international development secretary was a barely-known outsider when the leadership contest kicked off last month, and was widely expected to be one of the first to be eliminated.

No longer. An unconventional campaign combined with a straight-talking, honest approach and a strong stance against a no-deal Brexit have seen him catapulted into the spotlight and sent bookies scrambling to slash the odds on him becoming Britain's next prime minister (he is now the second favourite).

While some moderate Tory MPs increasingly think he is their best hope of stopping Boris Johnson bumbling his way into Downing Street, Stewart has a mountain to climb if he is to increase his number of votes from the 19 he received in last week's ballot to the 33 needed to progress beyond the latest round.

It would be far from the most arduous journey he has made. But who is Rory Stewart, the man who has taken the Conservative leadership contest by storm?

In a typically frank response to a question about weaknesses, Stewart told a televised hustings on Sunday that one of his biggest flaws was his privileged upbringing. He was born in 1973, the son of a British diplomat and deputy head of MI6, Brian Stewart, and his wife, Sally Acland Rose Nugent. Brought up in Malaysia, where his father was stationed, and then in Scotland, he was educated at Eton and the University of Oxford, where he studied Politics, Philosophy and Economics. While at university, he acted as a private tutor to Prince William and Prince Harry.

What came next is a matter of some dispute. The official version of events is that Stewart joined the Foreign Office and was stationed in Indonesia at the time of the crisis over East Timor's bid for independence, and then in Montenegro after the intervention in neighbouring Kosovo.

Other reports suggest he was, in fact, a spy. Given his father's position in the intelligence services, so the story goes, a young Rory was recruited soon after leaving university and served as an intelligence officer for seven years.

The MP denied this when asked by journalists on Monday if he had been a spy, as he would be legally obliged to do if he had indeed been a secret agent. But, pushed on the issue on Tuesday, told the BBC cryptically: "I definitely would say I served my country and if somebody asked me whether I am a spy I would say no."

There is more clarity about what he did next. In 2000, when he claims to have stopped working directly for the government, he walked 6,000 miles across Afghanistan, Pakistan, Iran, Nepal and India - a journey that became the basis of three widely-acclaimed books.

Stewart returned to the Middle East after the 2003 invasion of Iraq, becoming deputy governor of the Maysan province in southern Iraq.

After a short stint teaching at Harvard University, in 2005 he helped establish the Turquoise Mountain Foundation, an NGO working in Afghanistan in the wake of the US-led invasion of the country.

Brad Pitt was so interested in Stewart's story at this point that he bought the rights to make a film about his life, although the Hollywood star reportedly lost interested when Stewart became a Tory MP, winning the seat of Penrith and The Border at the 2010 general election.

He was quickly tipped as a future prime minister after entering parliament, but his political career got off to a slow start. He spent six years on the backbenches before being appointed to a series of ministerial roles, including prisons minister, where he raised eyebrows by vowing to resign if the state of UK prisons had not improved within a year.

Stewart finally got his break last month, when he was promoted to the cabinet as international development secretary in a reshuffle following the sacking of Gavin Williamson as defence secretary. It was, in part, a reward for his loyalty and his staunch defence of Theresa May's Brexit deal - a stance he has maintained during the leadership contest.

His appointment was mostly ignored, however, and Stewart remained largely unknown outside Westminster.

That changed when May announced her resignation as prime minister. Within days, Stewart had declared that he was standing to replace her, and kicked off a walking tour of Britain that saw him travelling around the country talking to voters and filming the conversations on a camera phone.

Initially seen as an entertaining but largely irrelevant outsider, his candidacy quickly gathered momentum. He won plaudits for his performance in the Channel 4 hustings on Sunday, and subsequently received some high-profile endorsements, including that of David Lidington, the deputy prime minister. May herself is even rumoured to have voted for him.

In an interview last year, Stewart admitted it would be "difficult" for him to become prime minister. For all the coverage his campaign has received, that has not changed. His support among Conservative MPs is growing but remains fragile, and his standing among the Tories’ Eurosceptic membership is low.

Still, the unlikely candidate running the most unconventional of campaigns has already achieved the unexpected. Few would now bet against him progressing to the next round, and the odds of him reaching the final two have rapidly diminished. Whatever happens next, Stewart is the clear winner of the contest so far. Many in Westminster are now asking: just how far can he go?