It started with a series of relatively minor insults from relatively unknown people on a programme watched by a steadily declining number of viewers. But by last night it had become something close to an international incident, with echoes of the inter-racial row sparked by the Danish cartoons of the Prophet Muhammad.

With the story of the alleged reality TV racism making headlines at home and abroad, in India, Australia, Egypt and South Africa, statements on the controversy were issued by Tony Blair and Gordon Brown to reassure the world that Britain was a country of "fairness and tolerance".

Dr Claire Heristchi, lecturer in international relations at Aberdeen University, said that she was not surprised the issue was being debated across the world.

"It would be naive to think that this issue would not reach India," she said. "It is part of the globalisation of popular culture. We need to get away from the idea that politics is something in parliament. The way in which people engage with politics is much more direct.

"This is something that calls for political response from a government because if they didn't, then domestically there might be an outcry.

"Big Brother benefits from this publicity. If Big Brother is a show where people say racist things, why are more people watching it now? It is a paradox."

The furore surrounds allegations that Jade Goody, her mother Jackiey Budden and boyfriend Jack Tweed, Danielle Lloyd and Jo O'Meara are bullying Shilpa Shetty, 31.

Ofcom said that it was looking into the 19,300 complaints which it had received about Big Brother so far.

Legal experts said that the contestants would face disciplinary action if they made the same comments in the workplace.

Richard Linskell, of law firm Dawsons, said he had "no doubt" that some of the comments would constitute racial discrimination or harassment if they were spoken in an office.

Jacqui McKechnie, a lecturer in psychology at Glasgow Caledonian University, added that bullying was a regular complaint of Big Brother contestants.

"There is often a bullying atmosphere in Big Brother," she said. "The difference is that Shilpa is from India so there is a racial dimension.

"But I don't think you can say that it is all racism. It is possibly more that you tend to be attracted to and get on with people who are most like you. It may have nothing to do with the fact that she's from another culture.

"People were upset when Carole Malone, the Sunday Mirror journalist was voted out. She was only put up for eviction because she had been talking about nominations with Cleo and Shilpa. The younger ones are almost blaming Shilpa because she didn't take any rap for it.

"It could also be envy. Shilpa is beautiful, successful, wealthy, charming and very dignified. If it is true racism it is unacceptable."

When she entered the house, Shetty said she wanted to "clear out the myths and misconceptions of Indian people: we are modern, intelligent and glamorous".

She added: "I have zero expectations. The only thing I really hope is to keep my self-respect and my dignity."

Ironically, she is now favourite to win the celebrity programme after a flood of bets for the award-winning actress were taken at bookmakers across the country.

Last night, Shilpa's mother was on her way to Britain. Talking from her home in Mumbai earlier, Sunanda Shetty said she was praying that her daughter would leave the show on Friday when she goes head-to-head for eviction from the house with Jade Goody.

She said: "To see her cry on TV while a bunch of people abuse her is a very painful thing for a parent."

Despite Channel 4 insisting there has been "no overt racial abuse or racist behaviour", Shetty revealed her own concerns in the diary room on last night's programme.

She said: "The most difficult circumstance is being without my family, to be with people from a different culture altogether, to bond with them equally.

"To adjust to different accents, they all have different accents, but only mine is singled out. I don't know why, I think they find it funny. We're all from different cultures and different backgrounds and different religions but we still have blood running through our veins, that's the only common factor."

Ken Livingstone, mayor of London, yesterday accused the producers of the reality show of editing the hour-long nightly programme to highlight the allegedly racist behaviour.

He said: "The mocking of Shilpa Shetty's accent, her Indian cooking and other aspects of her culture, as well as such basic things as repeated failure to get her name right and referring to her in extreme, derogatory terms are completely unacceptable.

"The company producing Celebrity Big Brother, Endemol, is editing down 24 hours of coverage to one hour and it is therefore clear they are choosing to highlight the racism of these participants."

The Commission for Racial Equality has said it is writing to Big Brother and continuing to review the programme.

A spokesman added: "It is not for the Commission for Racial Equality to take action on this matter at present. "It would be for the person who considered they were being racially abused to complain to the programme-maker in the first instance."

But Professor Mona Siddiqui, professor of Islamic Studies at Glasgow University, warned against focusing on the alleged racist element to the bullying.

She said: "I don't think that they saw her and thought: She's Indian so let's pick on her.' I don't think we should make too much of a racist thing out of it, I would imagine it is mainly a female issue and class issue. There are other non-white people in the Big Brother house.

"But it is probably a good thing that the audience is sensitive to this and people are concerned that we shouldn't have to watch this kind of thing, even if it wasn't intentional."

Meanwhile, as politicians, commentators and fans across the world are becoming embroiled in the controversy, the fifth series of the celebrity show has enjoyed soaring ratings.

Around 7.2 million viewers watched its launch episode but three days later the ratings had slumped to 2.8 million. They have now soared to 4.5 million.

What the Indian papers say

The allegations of racism towards Shilpa Shetty have made headline news in India, where national newspapers and TV programmes have debated the issue.

Although Big Brother is not broadcast in India, clips of Shetty, a popular film star, have been shown repeatedly on broadcast bulletins and newspapers' front pages.

The Times of India criticised the Channel 4 show, saying that Big Brother had "often been described as vacuous pap".

It labelled some of Shetty's fellow housemates as "a disgraced beauty pageant winner, an illiterate former dental nurse, pop star Michael Jackson's brother and a former teeny-bopper pop groupie".

It said that the Bollywood star had "unwittingly become the symbol of officially multicultural Britain's very public, sometimes two-faced, fight against racism".

It added: "Observers said Shetty, who was initially not in the running to win the show, may now have the bonus of benefiting from the racist bullying and actually stand a chance of winning."

The Hindustan Times, whose New Delhi edition claims to be India's biggest-selling English language newspaper, also featured the story on its front page.

Its sister Hindi-language paper ran the headline, "Shilpa faces racist abuse" and printed a photograph of Shetty wiping away a tear.

It said: "TV viewers in the UK are outraged at the racist treatment meted out to actress Shilpa Shetty on the reality show Celebrity Big Brother.

"Many viewers think Shilpa is being targeted out of jealousy: she is being paid more - $680,000 (£345,000) as against the standard fee of $610,000 (£310,000) - than anyone else. She has also been more popular in the media than any other participants, mostly B and C-list celebs."