Image copyright Getty Images Image caption The caste system originates in India but many British Asians say they suffer caste discrimination in the UK

India's caste system is thought to be among the world's oldest surviving forms of social stratification. However, some British Asians say they still experience discrimination due to their caste. So, why are so many Hindu bodies in the UK opposed to this being made illegal?

Sudesh Rani was shopping in the Home Counties two years ago when she experienced such discrimination first hand.

The 42-year-old from Bedford identifies herself as Ravidassia - a group regarded by some as at the lower end of the caste system. She says she was in a supermarket when two women began verbally abusing her.

Image caption Sudesh Rani says she was verbally abused due to her caste while shopping

"They started calling me a low caste chamar (a derogatory term used to describe an individual belonging to a low caste), a dirty bitch.

"At that time, I got a bit frightened, I thought 'no, no this can't be happening.'"

She said the women, who had seen her at a wedding previously, followed her and her nine-year-old son to her car.

"There were two of them and one of them was going to hit me, I thought they were going to really rip me apart.

"My son kept asking - 'mummy - what is a dirty chamar? Is that a swear word?'"

Ms Rani says the police did not know how to handle her complaint, because they had no idea about caste. Campaigners say cases like this highlight why caste legislation is needed in the UK.

In 2010, conversations began in the House of Lords about making caste discrimination illegal. A clause proposed for the Equality Act is currently awaiting the result of a public consultation.

However, many Hindu organisations are against legislation. Why?

What is the caste system?

Image copyright Getty Images

The caste system is thought to be an ancient Indian social hierarchy and a defining feature of Hinduism.

It is described as a hierarchy of four varnas - or caste categories - found in Hindu scriptures, with brahmins (priests and teachers) at the top, followed by kshatriyas (rulers and soldiers), vaishyas (merchants and traders) and the shudras (labourers and artisans).

Beneath them all are the dalits - so-called "untouchables" - who are completely excluded from society.

However, there is controversy over the extent to which caste is a feature of Hindu religion.

Some academics have claimed the caste system was introduced in its current guise during colonial rule in an attempt by the British authorities to classify and better understand the Indian society they were governing.

They assert that Indians have started behaving as if part of a caste hierarchy as a result of being taught to.

Legislating on caste is complex business, not least as many Hindus do not accept caste is an integral feature of the Hindu religion.

As a result, there are many who would prefer the issue remain under the radar.

Satish Sharma, chair of the National Council of Hindu Temples, is firmly against the proposed legislation.

While he believes there is no justification for caste-based discrimination, he believes the caste system has nothing to do with his religion and that any new law will present the issue as a Hindu problem.

He, along with a number of Hindus, maintains that the caste system as it exists now has more to do with the centuries of British colonial rule than ancient religion.

"This is not something that is part and parcel of our beliefs and ideologies," he says. "Our scriptures and our recent history up until a few hundred years ago didn't have this caste system in there. This is being directed at us, this has been put around our necks.

"Without even thinking about what it means, you automatically now gain the reaction 'dirty Hindus', that we're terrible and have savage ideals, that's what's automatically invoked whenever you mention caste. It's not part of our culture and we don't want it introduced."

Image copyright National Council of Hindu Temples Image caption Satish Sharma believes caste is not related to Hinduism

Mr Sharma is concerned about what he says is a lack of evidence for caste discrimination in the UK. He believes there is a "Hinduphobic" agenda behind those pushing for caste legislation that is leading to Hindus being unfairly discriminated against.

"There has been this assumption that Hindus are casteist and I have recently heard what I think is an outrageously prejudicial term, where groups who are not dalits are now being referred to as 'caste supremacists'."

But groups that represent victims of caste discrimination say they are not interested in the origins of the caste system, but instead want a new law to protect people.

"The Hindus - they need to actually do some soul searching on this and be honest with themselves and try and confront this thing," says Satpal Muman, from CasteWatch UK.

Nevertheless, he believes Hindus that claim the caste system does not originate in their faith have to confront their past.

"I do not understand why the Hindus want to oppose this call for equality. The only thing I can surmise from it is that they don't believe in equality. They want to perpetuate inequality so I really don't understand their mindset on this.

"Why the Hindus feel so victimised is beyond my imagination. They have to see the truth for what it is, you have to call a spade a spade. If you are unable to face the historical truth then you will never be able to resolve this issue."

Campaigners calling for caste discrimination legislation estimate there are up to half a million dalits in the UK who could be at risk of caste prejudice.

However, caste is not included in the census and there are no precise figures available.

Another issue complicating attempts at legislation is the fact many British Indians are unable to identify exactly where they fit in the fourfold hierarchy.

The experience of Dina Bhudia, a 42-year-old British Hindu, is typical of many.

She recalls learning about the caste system in religious education classes at school but is unable to reconcile it with her personal experience of her religion.

"I've never learnt about the caste hierarchy from any priest or temple," she says.

"They are not sitting there saying, 'right, us brahmins are here and you kshatriyas are there.'

"Technically I'm at the bottom of the pyramid. My granddad was a farmer, my dad was a bus driver, I'm a financial adviser - where do I fit in?"

For Ms Rani though, facing abuse because of her caste is something she still finds difficult to come to terms with.

"I was shocked and upset [after being abused], my son didn't sleep for days, nor did I.

"I've grown up here, I'm well educated, why should we have to suffer? We are just the same as everybody else."

You can hear the full documentary, The Caste Divide, on BBC iPlayer.