Standing few meters away from each other, the Khalistan supporters and pro-Indian group clashed with slogans and songs leaving the onlookers amused.
Dubbed as "Referendum 2020" the protest saw thousands of people from various countries including Canada, US, Australia and Spain demanding a separate Sikh land. Organized by a group called "Sikhs for Justice", the event intended to garner support for freedom of the alleged "Indian occupation of Punjab".
"We want referendum…it's our democratic right and no one can take that away from us", said Harjinder Singh who came from Birmingham.
The rally gathered at the historic Trafalgar Square in London with the event starting at 3pm GMT keeping in mind the local timings in India and US.
"The idea is to be heard because the Indian government wants to suppress our voices…but they cannot do that as we have international support now...one can see how the community has turned up", said Rahim, young man from Southall.
"This is only a beginning and we demand the government of India to a have a referendum as it's our right granted by the UN" said Jatinder Singh, one of the directors of "Sikhs for Justice" which organized the event.
A counter rally with banners and placards reading "United India" and "United, Diverse, Incredible" was just on the other side of the barrier. At one point both the rallies looked like they would clash but the police and people from both sides were able to stave it off.
Jay shah, a member of Friends of India Society International, accused the "neighboring country for meddling with India's internal issue" and added further that "India should not remain silent if they continued to support these kinds of events".
"These people don't matter…they are not the representatives of the great Sikhs of India" said Pravin Patel, Former Chairman of Sardar Patel Memorial Society in UK.
The speakers for "Referendum 2020" included controversial leaders like Lord Nazir Ahmed, Caroline Lucas and Paramjeet Singh Panna, who is "wanted" in India for a bomb blast in Punjab injuring nearly half dozen people in 2010.
Earlier, India had expressed its displeasure over the UK's consent for such a rally and requested its cancellation only to be spurned by the British, who didn't see any problem in a rally as long as "it did not endanger law and order".
A similar rally is planned to be held soon in Canada said the organizers.