Who is the FCA's new chief Nikhil Rathi and what did he do at the London Stock Exchange

One colleague talks of how he brought to the LSE Masala Bonds - bonds issued outside India but denominated in Indian rupees, allowing infrastructure projects and companies in the country to raise money from global investors. London is now the biggest global centre for the securities, with 49 bonds having raised more than $7.5 billion.

Similarly, he drove the exchange's push into the Chinese equivalent, known as Dim Sum bonds, as well as clean energy bonds, and led Rolet's mission to build closer relations with Chinese corporations through the Stock Connect system, which links the Hong Kong, Shanghai and Shenzhen stock exchanges. Stock Connect is widely seen as having got off to a slow start with barely any Chinese companies listing in London as a result of it.

At just 36, he went on to become chief executive of the London exchange under group chief Rolet, regularly hosting the chief executives and founders of new companies - including pop star Nile Rodgers - on the LSE's balcony for the tradition of opening the day's trading.

Says one colleague: "He's bright, but young enough to have emotional intelligence, too. He's easy to talk to and interested. A stand-up, nice guy."

Clearly a big family man, another staffer recalls how he once brought his mother in to the market opening ceremony. She and his father moved to London from their homeland of Madhya Pradesh in India in the 1970s before moving to Barrow when Rathi was a toddler.

The vegetarian had a reputation for starting early in the morning and being extremely hands-on as a manager, encouraging staff to approach him and keep him involved and engaged in their tasks.

He was deeply engaged at the LSE in figuring out how Brexit was going to impact on the exchange here, and how to ensure it keeps its place as Europe's pre-eminent trading hub.

Not often keen to talk publically about it, he told an interviewer in India in 2016: "The UK was never sufficiently converged wtih that of the rest of the EU. It retained its currency and the UK monetary authority had macro flexibilities."

"He had the right political brain to understand the ramifications," says a colleague, adding: "He also knows how Westminster works, which will serve him well at the FCA."

The LSE was not without its internal politics. Rathi - one of four divisional CEOs alongside the bosses of FTSE, LCH and Borsa Italiana - had a ringside seat as group boss Rolet saw his battle to merge with Deutsche Boerse torpedoed by German politicians. He then witnessed his mercurial boss's spectacular fallout with chairman Donald Brydon. While both titanic battles were going on, he kept his head down as the rocks flew over him.

He is seen as having struggled to build up the LSE's reputation as a place to list tech companies, where the US remains by far the more attractive destination for companies seeking capital. Also, the exchange's market for small companies, AIM is widely criticised for the high number of scandals among its members.

However, he is a regular at technology events such as the Founder's Forum Week where he was keen to press the LSE's appetite for young technology firms and claim the LSE itself was the world's biggest "fintech" firm due to its sophisticated technology.

He spoke regularly of his admiration of fintechs such as Transferwise and M-pesa. Fintech is a key focus of the Financial Conduct Authority as it attempts to encourage innovation in UK finance.

While once telling his local newspaper that he always felt most at home in Barrow, he now lives with his family in London.

Still only 40, his new role will inevitably led to speculation that he could become the next governor of the Bank of England.

Even if that doesn't come to pass, he has already come a long way from Cumbria.