If you are willing to admit that being rich makes one stuck-up, then there is your answer (though I am not willing to admit that, nor do I think it is correct).
Indians in the UK, on average are the wealthiest or second wealthiest ethnic group in the UK (above the white British but below/equivalent to the Chinese). Some people think that wealth makes people arrogant and stuck up. If you think so, then there's your answer.
Pakistanis are amongst the poorest ethnic groups on average in the UK (along with Bangladeshis) though Sri Lankans are fairly well off, so the wealth hypothesis is moot.
At the end of the day, every ethnic group has its stuck-up people, and its nice people.