London (CNN) The UK seems to be obsessed with the man at the heart of its new government.

He is widely regarded as a political genius. His name is in the papers every day. Some believe he was the single most important figure behind the country's decision to leave the European Union. And after three years of Brexit paralysis, he has promised to spend every waking hour in a herculean effort to make Brexit happen on October 31, do or die.

This man is not Boris Johnson, the new British Prime Minister , but his most senior adviser, Dominic Cummings.

If Johnson was the face of the official Brexit campaign, Vote Leave, Cummings was its brain. He is credited with creating the "Take Back Control" slogan and calculating the Brexiteers' widely-debunked claims that the UK sends £350 million ($424 million) to Brussels every week. Once a political outsider, he's now at the center of Johnson's efforts to prise the UK out of the EU in two months' time.

For this profile, CNN spoke to multiple British government officials, civil servants, and former colleagues of Cummings. Most agreed to be quoted only on the condition of anonymity to speak candidly. Some would not be quoted at all amid concerns about discussing one of the most powerful -- and sometimes feared -- men in the UK.

Almost everyone CNN spoke with agreed on one thing about Cummings -- his single-minded zeal to get the job in front of him done.

The Leave campaign's success, it's often said, was down to its singular focus on a simple message. And the decision to have such a simple message was made by Cummings.

"What sets him apart from many people is the unbelievable strategic focus on the task at hand. Dom's favorite phrase was always 'don't get stuck in the weeds,'" says Gisela Stuart, a former opposition party lawmaker who chaired the Vote Leave campaign.

Dominic Cummings was once a political outsider. Now he's at the heart of the UK government.

A loathing for elites

Cummings, 47, is not the sort of person typically associated with top-level politics. Despite having spent his whole career working for conservative politicians and a conservative think tank, he claims to have never been a member of any political party and loathes large parts of the governing Conservative party he now serves.

He has stated publicly that he had to be convinced to lead Vote Leave. "I wasn't massively keen to get involved with this," he said in 2017, claiming that he'd had enough of the Conservative party's infighting over Brexit.

Cummings largely shuns the spotlight -- Downing Street was approached for comment for this article but declined to provide any. He seems to revel in his reputation of being an irascible eccentric, his vast intellect perfectly matched with an instinctive understanding of how normal people think. Friends say he detests the political elites and relishes being seen as the strategic genius they all aspire to be.

As a close friend puts it: "All of the charlatans and spivs are courtiers to the people at the top of their parties. They are all looking at Dom because he is doing what they wanted to do. The only problem is, they're bulls***, they're just style. Dom is the substance."

His physical appearance can be messy: On the day Johnson took up residence in Downing Street, he was pictured in an old T-shirt, lurking in the corner. His manner can be bizarre: "He used to turn up to work wearing deliberately scruffy clothes and would quite often just sleep at his desk overnight," says a former colleague who worked with Cummings during his time as a political adviser to the Conservative party when it was in opposition.

Dominic Cummings is seen in the background (R) on the day Boris Johnson (L) first entered 10 Downing Street as Prime Minister.

Some colleagues find his behavior divisive. David Laws, a former Liberal Democrat lawmaker who worked with Cummings in the coalition government led by David Cameron, described him as a "Grade-A political rottweiler." He doesn't suffer fools and has a reputation for dismissing those he doesn't respect.

Such was the fascination with Cummings and his role in Brexit, he was portrayed in a recent biopic by none other than Benedict Cumberbatch. James Graham, who wrote "Brexit: The Uncivil War," says his decision to make Cummings the central character was easy. "He is different, and different is fun... He doesn't speak or talk or behave like other political strategists I have met."

Cummings was played by Benedict Cumberbatch in 'Brexit: The Uncivil War.'

Since entering Downing Street Cummings has embarked on a wide-ranging shakeup of the civil service and the army of government aides, known as "special advisers," or in the Westminster parlance "spads," multiple sources have told CNN. Longer hours, endless reams of paperwork preparing for Brexit and canceled vacations have become normal. Cummings' devotion to work and enormous energy is being instilled across government.

Yet despite this sudden increase in workload, it's hard to find anyone currently working with Cummings who has a bad word to say about him. Many civil servants and special advisers say that after former Prime Minister Theresa May's repeated failure to deliver Brexit, a single-minded commitment to leave the EU with or without a deal on October 31 has given them a fresh sense of purpose.

While Cummings' eccentric style had been evident earlier in his career, it was when working as an adviser to then education secretary Michael Gove in 2010 that his way of doing things began to attract wider attention.

He was reportedly dismissive of David Cameron and Nick Clegg, the Prime Minister and deputy prime minister for whom he and Gove worked. David Laws wrote in his book "Coalition" that Cummings once said to him while discussing education policy, "I don't like Clegg, but I think Cameron and No. 10 are muppets as well. They have no idea what they are doing."

Cummings eventually left this job in 2014. Then he let rip.

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In the years between leaving government and starting Vote Leave, Cummings retreated to his father's farm in the north of England and read. A lot. He would occasionally publish his thoughts on politics, politicians and more in long posts on his blog.

Here, Cummings mused on issues far bigger than the politics of the day. He wrote extensively about how artificial intelligence and machine learning were developing faster than the brains of humans, and the dangers presented by this development. He wrote about how, post Brexit, the UK should consider working with the entrepreneur Jeff Bezos to build a moon base to advance international cooperation and "create real long-term value for humanity."

And, of course, in almost all of these blogposts, he savaged the political establishment, both in London and Brussels, for its limited ambition and failure to prepare for what he saw as a longer-term crisis facing the human race.

What motivated a man who so hates the establishment and wanted to leave politics lead a campaign that ultimately placed him at the heart of it? "If the UK leaves on 31 October... I think in his view that will be halfway through the mission; the second part will be the reorganization of government," explains a friend of Cummings.

This ambition to change government is one side of the Cummings' master plan. The other is his belief that politics simply doesn't adequately serve the public.

Cummings was behind the debunked claims by Vote Leave that the UK sent £350 million a week to the EU.

Several former colleagues explained that his disdain for the ruling class came from his belief that for too long, the political elite had ignored the masses. In 2017, Cummings took particular aim at the Conservative party, claiming the view among much of the public was that it "is run by people who basically don't care about people like m... I am sad to say the public is basically correct."

And it's this single-minded drive that so many admire in Cummings that enables them to overlook his flaws. "He's eccentric, he's off the wall, but he's never, in my experience, been wrong," says a Conservative party insider who worked with Cummings in the coalition government of 2010 to 2015. "His political judgment is brilliant... everyone who is on the opposing side should be astonishingly frightened."

"Since love and fear can hardly exist together, if we must choose between them, it is far safer to be feared than loved," wrote the Italian diplomat Niccolò Machiavelli. That might have been true in 16th century Europe, but Machiavelli didn't have to deal with the UK's notoriously bureaucratic civil service, nor the intransigence of the European Union.

Could Brexit be his downfall?

Delivering Brexit rubs up against both of these obstructions. And it's here that even Cummings' admirers predict that his busy, take-no-prisoners approach to government could ultimately be his downfall. The civil service in London has a particular habit of wearing political appointments down. In Brussels, the EU also presents a challenge.

However popular Cummings might be now, some in Westminster think that his way of doing things isn't sustainable. "I would say that he is very good at delivering a short-term task and cutting through the bulls*** to deliver that. I am not convinced he will be around in government in long term," says one of his former colleagues.

Fortunately for Cummings, the job in hand has a firm deadline of October 31. After that, he might find himself eased out of Downing Street so that Johnson can begin governing more traditionally.

Cummings is a paradox that even Machiavelli might struggle to understand. He is simultaneously loved, feared and respected. People who disagree with his methods cannot deny his genius and privately wish he was on their side. And despite his career of rejecting the establishment and political mainstream, his star continues to rise.

It's worth remembering that in 2016, the Leave campaign was the underdog. No one believed that Cummings could pull off a victory for the pro-Brexit campaign. And even if the UK voted to leave -- as it did, narrowly -- the idea of leaving the EU without a deal was unthinkable. Now, it seems to be the most likely outcome.

"One of the best decisions that Matthew Elliot (chief executive of Vote Leave) made was to bring Dom in to run the strategy side of the Leave campaign. No one thought we could win the thing, but he had a plan, he stuck to it and it worked," says Daniel Hannan, a prominent Leave campaigner, and friend of Cummings.

The outsider who defeated the British establishment now stands inside the most important building in London, ready to take on the Brussels establishment. The odds are stacked against him, and some believe his project is doomed to fail.

But if history tells us anything, when Cummings seizes a plan and sticks to it, his opponents tend to break first. It's little wonder that Boris Johnson wanted him by his side as he embarks on the most controversial period in British political history.