Partho Shome says he’s walking a lot nowadays. It’s what you do in London, he says, and he’s enjoying every bit of it. He’s also spending his weekends house hunting. There are so many decisions to be made: whether to live in central London in a small place or opt for leafy suburbia and commute.

After three years in India, in the spacious surrounds of his Pandara Park house in Lutyens’s Delhi and being ferried to work in an office car, Shome is slowly getting used to the lack of space in London flats, and the walking.

It’s been barely three weeks since one of the chief proponents of Indian tax reforms quit his high-power job in India as adviser to the finance minister, P. Chidambaram, and joined Her Majesty’s Revenue and Customs (HMRC) — the British tax office — as economic adviser. He is the first Indian to be appointed to a senior post in the British government.

No wonder then, that when he informed Chidambaram of his decision to leave late last year, the finance minister could only say: “Is it as prestigious as what you are doing now?” Prime Minister Manmohan Singh, who had been on the faculty when Shome was a student at the Delhi School of Economics, needed a lot more persuasion to allow him to resign.

“I finally managed to persuade Dr Singh, my former teacher, to let me go,” smiles Shome. “I told him it would be mutually beneficial for both the UK and India.”

Sitting in a meeting room in the HMRC building on Parliament Street, a few yards from 10 Downing Street and the Houses of Parliament, Shome looked very much at home. The room was stark and functional — a white melamine table and four red bucket chairs. The press officer from HMRC sat in on the interview taking notes, just in case. After all, Shome’s is a sensitive appointment. It even needed a special waiver from the Public Service Commission in the UK — which looks at appointments for senior government bodies — to get him through the hallowed doors of Her Majesty’s Treasury.

Down the corridor from his room was the balcony from where Winston Churchill famously addressed the crowds on VE Day to announce the end of the war in Europe. And it was in this building that Gordon Brown, then Chancellor of the Exchequer, took the call from the Queen after the resignation of Tony Blair, and left to take over as the new Prime Minister.

The former International Monetary Fund (IMF) executive was plucked out by Chidambaram in 2004 from New Delhi’s National Institute of Public Finance and Policy, of which he was then director. As Chidambaram’s adviser, Shome oversaw three budgets, introduced the online filing of tax returns, the value added tax and the fringe benefit tax and steered the simplification of the tax process in India. His resignation — just two months before the new budget — fuelled media speculation that he was fed up of the bureaucrats in the finance ministry, something Shome denies.

“That has been misrepresented,” he says. “I have nothing against bureaucrats. I come from a family of bureaucrats and have worked with bureaucrats in several countries. I do, however, feel that specialisation is of great importance. People should be brought in from the private sector as it allows for dynamism. My premise has always been public/private partnership.”

As for working with Chidamabaram, a man who can lose his cool and doesn’t suffer fools gladly, Shome is diplomatic: “I worked with him closely for three years and never had a problem.” But he shrugs when I say he is likely to meet his former boss frequently in London. “I am an HMRC man now. It’s going to be taxes for the next three years!” He has not yet met anybody from the Indian High Commission and says he’ll go there for functions “if he is invited”.

It was while travelling with Chidambaram over the last few years that he interacted with the finance chiefs of the British Treasury. Dave Hartnett, director general of HMRC, was so impressed that he discussed the possibility of Shome joining his department. Shome was open to the idea and within two months the British government had poached him from North Block. The 57-year-old is seen as a “thought leader” in the HMRC, overseeing, besides other departments, a specialised cell called “Knowledge, Analysis and Intelligence” (KAI), a key body that will be the hotbed of intellectual activity and handle policy recommendations for the Treasury. Given that it is often taxes on which elections are lost and won in the West, the job is no small one.

For Shome, it all began when he graduated from Presidency College in Calcutta, topping the university. It wasn’t the legendary “first class first” that all Bengalis aspire to, however. “It was 1970, the height of the Naxal uprising. Everything was so chaotic they said you can’t get a first class,” says Shome. “They took away four marks…,” he adds ruefully, clearly still hurting from that.

It was goodbye to Calcutta after that. Shome moved to Delhi to do his masters degree at the Delhi School of Economics where his lecturers included, apart from Singh, Amartya Sen. The move westwards continued. He completed a second masters degree from Rochester University and then moved to SMU in Dallas, Texas, for his PhD. “Sometimes I wonder what would have happened if I had studied at Oxford instead,” he muses. As it happened, the stint in Texas honed his skills as a fiscal economist and in 1983 he joined the IMF at the age of 32.

Over the next few years Shome criss-crossed South America from Venezuela to Chile, earning a formidable reputation as the IMF’s chief fiscal repairman. Barring two countries — Honduras and El Salvador — he travelled to every country in South America and helped their governments to overhaul their tax structures and get the economy back on track. He spoke fluent Spanish, collected South American native art, immersed himself in regional literature and was offered an honorary citizenship by several of the countries. Brazil gave him the equivalent of a knighthood and Argentine officials moaned, “Why do we lose you?” when he left. To many of the Latin American governments, the soft-spoken Bengali was a hero. To Shome, Latin America was where his heart lay. “They have a very emotive culture,” he says. “I have some very good friends there.”

So what is the man, whose handling of failing economies in developing countries is legend, going to bring to the developed world? Shome brightens up immediately. Clearly, as far as he has seen it, the British tax structure needs help too.

Shome’s mantra for a successful tax structure is one word: simplicity. “Simplicity brings friendliness,” he says. “There has to be accessibility, a response centre for people to go to with their queries and the key elements understood by every tax payer.” He is going full-steam now, rapidly taking me through the maze of departmental committees that he will oversee at this 80,000 staffed office. Perhaps that dreaded tax form which comes through every household letterbox in Britain after April 5 — usually shoved hurriedly to the bottom of the drawer and filled only when the deadline is menacingly close — will look a little friendlier from now on. India’s loss may well be Britain’s gain.

Once he’s found a house, Shome is keen to soak in the art and theatre scene in London. Happily single, he has had the freedom to travel the world and is a voracious reader and a keen collector of art. Significantly, it is not the much-discussed Matisse exhibition at the Royal Academy that he tells me he wants to see, but the exhibition by Colombian artist Doris Salcedo at the Tate Modern. “Colombia is my favourite country in South America and I read about this exhibition,” he says enthusiastically. “I’ll definitely try to go and see it.”

Apart from the house hunting, the long work hours at the HMRC are giving him little time for anything else at the moment. After a 100-minute commute from a friend’s place, he enters his office by 8.45 am and is there till 7.30 in the evening, followed by a long commute back. “It’s tiring, but I think I’m going to enjoy it here,” he says enthusiastically. Amazingly enough, I think he will.