Several groups representing Sikhs, Nepalis, Kashmiris, and women's groups came together at midday to highlight their claim that minorities are particularly suffering under Narendra Modi.
Modi, the leader of the nationalist Bharatiya Janata party, has been accused of stoking religious tension and clamping down on freedom of speech in India.
He has been unable to shake off claims that he didn't do enough to stop thousands being killed in 2002 when riots took place in Gujurat while he was chief minister for the western state. Three British citizens were burned during alive the riots. Six people were accused of burning the tourists, but were later acquitted.
Jagdish Kaur, 26, said a huge number of Sikhs were facing persecution from Modi in India and accused the British government of facilitating Modi's attempts to ignore claims of human rights abuses.
She told BuzzFeed News: "He shouldn't be wined and dined by the Queen because it seems like she supports his actions. The UK should at least has some moral compass with which we're operating."
Dozens of Sikhs waved flags at the protests in memory of those who have died.
Meanwhile, Nepali protesters demanded that the Indian government end a blockade that is stopping essential items like petrol and medical supplies from entering Nepal at border crossings throughout the country.
Up to 100 Nepali protesters gathered on Whitehall and chanted "Back off Modi". Tara Paudel, the president of the Nepalese Women Helping Hands organisation, accused Modi of "standing by" while people were dying.
For its part, India has denied it has imposed a blockade.
There were also a large number of Kashmiris who said they were protesting against illegal occupation of Kashmir by the Indian army.
Dr Yasin Rehman, a PhD academic, accused Modi of having an "extremist personality". He said that the group was protesting to "send a message to Modi that the people of Kashmir will never compromise in freedom".
Responding to a claim by employment minister Priti Patel that things have "moved on" since the Gujurat riots, he said: "You can never move on from Gujurat. There should have been a proper investigation at the time. If you ask the people of Gujurat if they've moved on, they'd say no."
Modi will be in the UK until Saturday. In direct contrast to the hostile welcome he received on Thursday, he is expected to be greeted like a rock star on Friday evening at Wembley Stadium, where 60,000 people are expecting to turn up to celebrate the visit. He will be introduced to the large crowd by prime minister David Cameron.
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Siraj Datoo is a political reporter for BuzzFeed News and is based in London.
Contact Siraj Datoo at firstname.lastname@example.org.
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