Islamic groups say authorities should arrest Narenda Modi, the chief of India's Gujarat state, when he visits London to give a speech to Hindu supporters on Sunday.
The groups say he is a war criminal and his visit will damage community relations in the UK.
Human rights groups accuse Modi of inciting the murder of up to 2000 Muslims in communal riots in Gujarat last year.
Massoud Shadjareh of the Islamic Human Rights Commission, said rights groups would demonstrate outside the conference hall where he is due to speak.
“It is an outrage the UK authorities can let a person like him come here. It is sending everyone a message that those who commit crimes against Muslims will be rewarded as long as they are still in power,” he said.
“I detect clear double standards here with the treatment of Muslims and, for example, the Jewish community. If Modi were responsible for the genocide of Jews it would be a different story," he added.
“Instead, just like war criminals such as Milosevic and Mladic before him, he is given the red carpet treatment.”
Shadjareh called for the UK police to arrest Modi as soon as he steps foot on British soil.
“Modi should be treated as a war criminal. The precedent has already been set in the UK with the arrest of Chilie's General Pinochet a few years ago.”
However, a British Foreign Office spokesman said there is insufficient evidence to deny Mr Modi a UK visa.
He said: “Modi's visit is not associated in any way with the British government and we want nothing to do with it.
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"But it is true we granted him a visa because, after consultation with police and other agencies, we concluded there wouldn't be enough risk caused by his visit to prevent him from coming."
He added: "We are extremely concerned by the situation in Gujarat and we are aware that groups have condemned Modi.
"We are also aware that people will be upset by his visit, but at the moment we are waiting for the Indian courts to pass judgment on his role in the communal unrest.”
Riots broke out in Gujarat in February 2002 after 60 Hindu pilgrims were burned to death on a train.
About 2000 people died in the ensuing reprisals against Muslims, along with mass rapes of hundreds of women and destruction of properties worth millions of pounds.
First reports alleged the train torching was carried out by a Muslim mob, but a subsequent report by forensic scientists proved inconclusive.
Respected human rights groups blamed the Hindu nationalist state government of Gujarat for orchestrating the violence.
Mr Modi was castigated for turning a blind eye to the anti-Muslim attacks and, some say, actively encouraging them.
A Human Rights Watch report said: "What happened in Gujarat was not a spontaneous uprising - it was a carefully orchestrated attack against Muslims.
"The attacks were planned in advance and organised with extensive participation of the police and state government officials."