British Indians in one of the country’s most diverse boroughs have warned against attempts to divide voters in the general election along ethnic or religious lines.

Last week, a UK support group for the BJP, India’s ruling Hindu nationalist party, said it was campaigning for the Tories in 48 marginal seats. It also emerged that WhatsApp messages were circulating among British Hindus urging them to vote against Labour, accusing it of being “anti-India”, raising fears that tensions are being stoked ahead of the election.

But when the Guardian visited the north-west London suburb of Harrow on Monday, home to the highest density of Gujarati Hindus in the UK, people criticised the BJP’s involvement.

“They don’t have to interfere in the politics here,” said Suresh Morjaria, a 67-year-old shopkeeper. “They can do what they want in India. I am happy for them to do what they want with [Indian prime minister Narendra] Modi, but this is a different country.”

The president of Overseas Friends of BJP UK, Kuldeep Singh Shekhawat, boasted to the Times of India that the group had recently invited 300 Indian-origin constituents to a meeting with the Conservative MP Bob Blackman from Harrow East (1,757 majority) and the Tory candidate for Harrow West, the British-Bangladeshi Dr Anwara Ali, who is fighting to overturn a 13,314 Labour majority.

Blackman also hosted a Diwali event – a Hindu festival – in the House of Commons last month, from which Labour MPs were reportedly banned, and which an attendee told the Guardian the event “was all about vote Conservative, and nothing to do with the festival of Diwali”. When the Guardian went to Blackwell’s constituency office to find out if the BJP were canvassing for him, it was met with a “no comment”, and staff did not reply to emails.

Harrow is an obvious target for the BJP, given that 26.4% of the population in the area are British Indians, according to the 2011 census, second only to Leicester. But none of those the Guardian spoke to said they would cast their vote based on UK policy towards India and all rejected BJP interference.

“It’s wrong,” said 34-year-old hairdresser Kamlesh Nayee. He shook his head when it was suggested the BJP were angry over Labour’s stance on the disputed territory of Kashmir. “Labour is good,” he said. “I got my [British] passport under Labour. They helped me, they understand.”

He was not the only one to cite other issues as being closer to his heart. Jemma, 25, a youth worker who did not wish to give her second name, said: “Education is important. I’ve got a lot of young people [I’m working with] from the EU who are being penalised [by Brexit uncertainty].”

She also worried about the impact of the BJP support group’s WhatsApp messages . “Everyone in my family from the old generation doesn’t understand it and they’re very affected by what they received so I have tried to block them on my mum’s phone.”

Sairah Anwar, 78, originally Kenyan of Indian extraction, is married to a Muslim and said she knows firsthand the tensions. “Most of the people from India or Pakistan they don’t get on with each other,” she said.

But Anwar stressed people should not be encouraged to vote on ethnic or religious lines. “They shouldn’t say that,” she said. “People should think for themselves.” She was still deciding which party to vote for, but like many other British voters, geopolitical considerations like Kashmir were far from her mind. “I was going to go Labour but I don’t like the man [Jeremy Corbyn]”, however, she added: “I also don’t like [the Conservative home secretary] Priti Patel.”