The protest was mainly organised by a host of Sikh organisations seeking release of Sikh prisoners in Indian jails.
The Sikh demonstrators were supported by Kashmiri groups who also joined the protest carrying flags of Kashmir.
The Sikh protesters carried banners demanding the creation of Khalistan, and protested imprisonment of Sikh activists by Indian government for posting Facebook messages in support of Khalistan and detention and convictions of dozens of Sikhs on bogus charges.
The protesters said that amongst those detained by India were British nationals who were picked up and convicted during their visits to Punjab in India.
They mentioned, in particular, Ranjit Singh, Surjit Singh and Arvinder Singh, who were jailed over Facebook posts.
The protest continued peacefully till a pro-Modi group arrived on the scene and started shouting abuses at the peaceful protesters and produced placards disrespectful of Sikh religious symbols.
In the clashes that followed, the whole of area around Holborn and the London School of Economics was brought to a standstill for sometime as dozens of police vans arrived to police the protest.
Bottles were thrown on Khalistani and Kashmiri protesters from Modi supporters and then the clashes started.
Activists from both sides exchanged fists and the Indian flag was brought down by Sikh protesters from outside the Indian High Commission.
Three people were injured during the clashes.
Farid Qureshi, a Pakistani reporter working for a private channel, received injuries to his nose and eye after he was hit with an object during the fight. He told this scribe that he was performing his duty when he was attacked.
The police ambulance provided him first aid along with two other injured.
Two protesters were seen being handcuffed by the police for getting involved in the physical fight.
One protester was seen with blood pouring down his face.
Joga Singh of the World Sikh Parliament, speaking to the gathered international media, called for urgent steps to stop a war that would devastate the Sikh homeland and population.
Amrik Singh Sahota, Council of Khalistan, urged Sikhs and Kashmiris in Indian-controlled territories to act to stop the war and for Sikh soldiers to return to Punjab and protect its people in case full-scale hostilities break out.
Dupinderjeet Singh and Parmjit Singh Pamma, Sikhs for Justice, demanded that a plebiscite in Kashmir be held, along with a referendum in Indian-occupied Punjab so that democratic outcomes may underpin permanent resolution of conflicts in those regions.
Balbir Singh Bains, Sikh Relief, called for the immediate release of Sikh political prisoners by India, including three recently jailed for life simply for non-violent activism linked to the Sikh struggle for self-determination.
Kashmiri leaders also urged global action to follow up the UN High Commissioner for Human Rights 2018 report calling for a halt to Indian hostilities in Kashmir and the delivery of long promised self-determination in the disputed territory.
Naeem Abbasi of Overseas Pakistanis Welfare Organisation said that the international media’s exposure of India’s false claims over its “air strike” last month had already badly damaged Modi’s propaganda efforts.
He said: “Going by events in London today, his Hindutva agenda will face many more challenges in the weeks and months ahead.”