His effigy has been burnt, the Congress leadership has tried to denounce its authenticity, attacked him at press conferences – but Javier Moro, the Spanish writer whose The Red Sari, a fictional biography of Sonia Gandhi has just come out, is unapologetic. "It's much better to write an unauthorised biography – what can be more boring than an authorised biography," he asked the crowds gathered to listen to him speak about the controversial book at the front lawns of Diggi Palace on day three of the Zee Jaipur Literature Festival (ZeeJLF). "She may be a private person, very shy. But she's a public figure and can't escape being written about," he emphasised.

The Spanish edition of the book, the result of five long years of research that saw him trace her life from the village of Orbassano, where she was born, through her school, college, later England where she met Rajiv Gandhi and later India, was published in 2008. The English version was to have come in 2010, but for the opposition from Sonia Gandhi and the Congress who even tried to stop its release in other English speaking markets, said Moro.

And this despite several attempts by Moro to get Gandhi to give the book her blessings. "I met her at a function to felicitate Dominique Lapierre [Moro's uncle] at the Rashtrapati Bhawan, went up to her and told her jokingly, 'Madam, four years I have been sleeping with you,'" referring to the years he'd been researching the book. Gandhi however, he said, turned him away, saying, "We never read anything written about us. "It was a pompous and I was surprised because she is not a pompous person," Moro commented.

Despite all the controversy and the Congress campaign, Moro's book actually paints quite a flattering picture of Gandhi, depicting her as a simple woman from a humble background who fell deeply in love with her husband-to-be, and so left behind her familiar world, disregarding all her father's dire warnings, to be with him and make his family and country her own.

Moro, however, denies the charge – "My book humanises her." So it gives details about Sonia's birth, what she was like in school ("docile"), how she met Rajiv, the couple's struggles to convince her father for whom, says Moro, "marrying an Indian was like marrying a Martian", the first and subsequent cordial meetings with Indira, their marriage, life in Indira's Akbar Road household, some bits about the friction between Rajiv and Sanjay, the Emergency and later Rajiv's joining politics and becoming PM – through all of which Sonia comes through, in Moro's narrative, as single mindedly focused on Rajiv and their tight, undoubtedly happy family life. But there's nothing about the grey areas - Bofors, for instance, or the Gandhis' alleged role in shielding their friend Quattrochi, or even an unsentimental, convincing account of what exactly made her turn to politics.

"If I were an Indian reporter, I would have gone into Bofors in greater depth," Moro cries off, adding that he was not writing the book in order to judge her. Instead, he tends to the other side. "I have never believed the Gandhis were corrupt people. I have seen the house she has lived in, the house she sold five years ago. Yes, they may have had friends who were corrupt," he said. As for her son, Rahul, Moro is similarly indulgent: "The Gandhis have always been late bloomers."

If, as you say, there is nothing in the book that puts her in a bad light, then why is the Congress so angry?They did it, I think, to please the lady. They possibly could not have read the book when they did that, because there was no English version. It was all hearsay, or taking lines out to context.

Was it because your book shows her as a normal person?She is not a goddess, that p**ssed them off. That I had dug into her past, went into the village where she was born. I was trying to be as close to facts as possible. Of course I did not do anything damaging. I think it was mismanaged – and if they mismanage such a little thing, one imagines the results with the elections.

Where did she acquire such a sense of eminence grise? "We don't read…" and all that?That's because she is surrounded by sycophants. You can resist that for certain number of time, there is a moment when you end up believing it.

But you've only perpetuated the myth of Sonia…No, I have only humanised her - how did she fare, what were her fears, how did she decorate her house, how efficient was she in her household chores because she did that for years, how ambitious, or un-ambitious was she, how did she dress her kids, how did she help dress her mother-in-law every time she went out. This is human-making; the myth-makers are the Congress who made a marble statue out of her, inhuman, above the world.She's always been a very simple person, she still is. She cares about family, she finds her peace in little things.

Did you have informants within Congress or 10 Janpath? How did you get intimate details like it was Priyanka who got her medicine when she had an asthmatic attack after getting the news of Rajiv's death? Did she try to stop others from speaking to you?She couldn't have done anything. I interviewed Christian from Stiglitz, who introduced Rajiv Gandhi to Sonia at Cambridge, because he wanted to talk – there was nothing bad he was going to tell me. We became friends. [Other, later details about events at 10 Janpath] probably came from books by Pupul Jayakar, who was a very good friend of Indira Gandhi's, and Katherine Frank. I knew that Sonia asthmatic, so it might have been poetic licence to have her daughter bring her medicine.

What do you think of her subsequent career as a politician?The new epilogue summarises what I think of her governance. I think she did what she had to do. She was faithful to her constituency, the poor people who voted for her; she fought hard to have the social policies implemented against the liberal [economic policies of the] government that was hampering them.

But she didn't become a citizen of India until much later, in the 1980s.So what? Why would she? It's only the opposition who made a big fuss about it. When Rajiv became prime minister, he had to have a wife who was Indian. It doesn't mean she didn't feel Indian – she'd lived in this country, she knew Hindi, she had two kids here, she wore saris. She had adapted totally.