They chose the wrong time – and the wrong place. This was certainly not the time to launch a book critical of Mother Teresa – days before her canonisation in the Vatican on Sunday. Calcutta is readying itself, not to receive any such book, but to bask in the glory of its first-ever saint. It is not often it gets a chance to pat itself on the back.

The book is not exactly new. It’s a translation into the local Bengali language of an English one, Mother Teresa: The Final Verdict, by Aroup Chatterjee, a Britain-based physician, published in 2003.

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The writer grew up in Calcutta and worked in its slums as a volunteer before moving to Britain. The Bengali version was to be launched on the premises of the University of Calcutta. On the eve of the launch, the publishers were told by the authorities that their booking of an auditorium of the university had been cancelled due to “compelling reasons”. The doctor, 58, who sees himself as the “lone Indian” to have written a book critical of Mother Teresa, was due to arrive in the city on Thursday from Germany to take part in the launch at another venue.

Calcutta, though, is not letting Chatterjee or his book spoil the mood. At the centre of the celebrations is the Mother House, her home for nearly four decades and the headquarters of the Missionaries of Charity, where she lies buried. In life, she made it the city’s only must-visit place for princes, prime ministers and popes. Now, 19 years after her death, her sainthood will make that home, at the end of a narrow alley in an impoverished part of the city, a pilgrimage centre.

Through the small entrance door facing the alley I walked one October evening in 1979 to interview her hours after her Nobel Peace Prize was announced. Her dislike of journalists and photographers was common knowledge among local scribes. There she sat amid bare walls, just a few chairs and no table – almost a mirror image of the simplicity that she preached and lived.

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But she smiled a lot (she did that all the time while meeting people) as she muttered her replies, almost in whispers, to my questions. It wasn’t a long interview. Far from it, because she had very little to say except that she accepted the Nobel on behalf of the city’s poor whom she loved. God, love and the poor were her answers to almost anything I could think of asking her.

It was another interview, though, that launched her on the world stage – the one by British journalist Malcolm Muggeridge on the BBC in 1968. Talking of the “poorest of the poor” during that interview, she said: “In these 20 years of work among the people I have come more and more to realise that it is being unwanted that is the worst disease that any human being can experience. For all kinds of diseases there are medicines and cures. But, for being unwanted, except there are willing hands to serve and there’s a loving heart to love, I don’t think this terrible disease can ever be cured.” Muggeridge, an agnostic all his life until then, was so moved by the interview that he converted to Catholicism.

The book he wrote, Something Beautiful for God, and the film made from it, spread Mother Teresa’s fame far and wide. Over the years, she became the Roman Catholic Church’s top fundraiser and its best known flag bearer. There have been other critics, though, the most high-profile of them being Christopher Hitchens, whose book, Hell’s Angel, and the film based on it remain the strongest censure of Mother Teresa and her work. To Hitchens, she was “a demogogue, an obscurantist and a servant of earthly powers”.

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Others have castigated her for raising funds from dictators and other shady characters. “No matter how rancid the catch, all’s fish that comes to Mother Teresa’s net”, snapped one critic. Feminists like Germaine Greer pilloried her for her staunch opposition to abortion and birth control, accusing her of ignoring the issue of women’s health.

All those who came to know Mother Teresa found in her a strong-willed personality who would not buckle under criticisms and have her way against all odds. The Missionaries itself is the best proof of this – an organisation that she founded with the help of just 26 assistants that now has more than 500 centres in 133 countries. One story popular in her lore shows how she got things done. She once needed five acres of land in the capital New Delhi to open a centre for leprosy patients. Others whom she asked to help failed to convince the bureaucrats who could allocate the plot. At a meeting with Delhi’s lieutenant-governor, she so impressed him that she walked away with not five, but 11 acres.

The latest to change positions on Mother Teresa is none other than the Indian prime minister, Narendra Modi. In the most recent edition of his monthly radio talk to the nation, Modi noted how proud he felt about her canonisation. The Indian government is sending an official delegation, headed by its external affairs minister, to Rome to attend the canonisation. But some Hindu, rightwing leaders of the prime minister’s own party have seen red in Modi’s change of heart. The ruling Bharatiya Janata Party has always accused Mother Teresa of using her work as a “ploy” to convert poor people to Christianity.

Modi, the politician, however, knows better which way the wind is blowing. He knows a Saint Teresa could add much to his Shining India campaign.

Ashis Chakrabarti is a senior editor at The Telegraph in Calcutta