Monica Ali is angry. Praised to the skies for her first novel, Brick Lane, an international bestseller and a British literary sensation, she has just discovered the flip side to fame and fortune. An 18-page letter from a committee called the Greater Sylhet Welfare and Development Council, which claims to represent Britain’s 500,000 Bangladeshis, accused her of stereotyping their community in her acclaimed work.

The group calls the book a “despicable insult to Bangladeshis at home and abroad” and has demanded Ali’s portrayal of their community be withdrawn from circulation for “corrections”. The letter was sent to The Guardian in advance of its First Book award for which Ali had been nominated. What has infuriated Ali is the comparison being drawn between Brick Lane and The Satanic Verses by Salman Rushdie.

A clutch of literary luminaries from this year’s Booker prize judges to Oxford professors was wheeled out to draw the distinction between fiction and fact, but the damage has been done.

Sitting in the small south London cafe, the shy, intelligent young woman at the centre of this row is careful to point out that the GSWDC is entitled to its opinion but she believes that The Guardian played up the Rushdie parallel in its reporting of the letter. “It’s irresponsible on so many levels. They have used the comparison with The Satanic Verses in that casual and utterly baseless manner. I have two small children. Don’t they realise it’s people’s lives they are playing with?” she said.

Her fears are understandable. Rushdie, in fear of his life, had to live with bodyguards for a decade. The GSWDC’s demand to Doubleday, Ali’s publisher, that it be allowed to “correct” her fictional portrayal of the Bengali community has a sinister precedent. Earlier this year Ali was refused a visa for Bangladesh despite being born there. Although she has said, “I don’t feel the need for allegiances. To me, home is nowhere in particular”, it is clear that some of the reaction to her novel has appalled her.

“Bengali people in this country are very sensible and will not be led into silly, irresponsible behaviour, but all it takes is one nutcase — every country and community has its nutcases — and it only takes one . . .” Her voice, strained from tiredness, cold and stress, fades away and she says: “Words fail me.”

For Ali to say this is quite clearly horrible, not least because she is a writer who has given a voice to a minority whose life and customs have been veiled to the majority. Her story of Nazneen’s arranged marriage to the pompous, frustrated Chanu, and her voyage from the hard mud floor of a Bangladeshi village hut to London’s Tower Hamlets, illicit love and intellectual freedom has struck a chord with readers all over the world — including countries with no Bangladeshi immigrants. It is Chanu’s dismissal of his own countrymen that has caused offence. “Most of them have jumped ship,” he says in the novel. “They have menial job on the ship, doing donkey work or they stow away like little rats in the hold.”

The GSWDC’s complaints, which include the observation that some Bengalis live in smart houses with swimming pools and that Chanu’s words will give readers “the idea that Bengalis are uneducated and cannot read”, are ominous.

Ali is appalled at the “infantile” confusion between the views of a fictional character and her own. Chanu is drawn with compassion and an assured comic touch that the GSWDC seems to have missed. She has not, she says, had this reaction from her many contacts in the Bangladeshi community.

“I’ve been getting so much positive feedback from Bangladeshis in this country and New York and all over the world when people came to my readings. I’ve had little Bengali grannies coming up and hugging me and saying they were so proud. The Newham Group of Asian Women invited me to speak at their general meeting in the East End, where I was cheered by 250 women; I’ve been asked to become a patron of the Attlee Foundation’s new youth centre and BritBangla, a network of dynamic young Bengalis, has made me an honorary member.

“I'm totally mystified by this council — which I’d not heard of before. I have documentary evidence that readers of all colours understand that Brick Lane is written with love and compassion, sympathy and empathy for all its characters.

I checked with a youth worker in the East End, and he told me, ‘If there were all this anger I’d be hearing it in the mosque and in the street’.”

Ali herself may live in the raffish end of Dulwich, south London, and eschew the society of the literary elite, but she attended a fee-paying secondary school (although she points out that she was awarded a free place) in Bolton, Lancashire, and read PPE at Oxford. Simon Torrance, her husband by whom she has a four-year-old son and a two-year-old daughter, is a management consultant and she worked for Verso, a small publisher, which is the kind of job many middle-class graduates aspire to.