On Wednesday, Pakistan-backed PoK and Khalistani elements burnt the Indian flag in Central London while the London Metropolitan Police quietly watched the flag burning taking place right before its eyes.

The incident took place at Parliament Square as Prime Minister Narendra Modi was addressing the Indian community at Westminster on Wednesday.

Indian activists are outraged over the London Metropolitan Police turning a blind eye to the Indian flag being pulled down from a pole and replaced by a flag representing PoK and Khalistan.

Reacting to the incident, the Indian government strongly protested with the UK government about the flag being removed and burnt by Khalistani elements in London.

A top Indian government source said that the UK government has apologised for the act, replaced the flag and is taking action against the perpetrators.

The Indian tricolour was allegedly pulled down and ripped apart by a pro-Khalistani activist.

Some of the protesters at Parliament Square yesterday turned aggressive after the Indian tricolour was torn down from the flagpole.

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A senior broadcast journalist from one of the leading Indian media channels covering the protests was caught in a violent scrum with some of the more aggressive pro-Khalistani protesters and Scotland Yard officers on duty had to step in to the rescue. The group is planning to file a complaint with the Metropolitan Police on the incident.

"We have expressed our concerns with the British authorities and they have apologised for the incident. We have been warning against some of these elements out to make trouble and they have assured us of action. The Indian flag has now been replaced," a senior Indian official associated with the PM's visit said.

The pro-Khalistani demonstrators from Sikh Federation UK and demonstrators from the so-called "Minorities Against Modi" group, led by Pakistani-origin peer Lord Ahmed, were among nearly 500 protesters who descended upon Parliament Square. These included groups led by some Kashmiri separatist groups and at one point, some of them had surrounded the Mahatma Gandhi statue at the square with their banners and flags.

Officials involved with the prime ministerial visit to the UK had said that protests and demonstrations are "part and parcel of any democratic society" as long as they remain peaceful. There are now concerns that some of the more aggressive elements hijacked the tone of the protests.

Earlier on Wednesday, flash mob of sari-clad women with dhols set the tone for the pro-Modi crowds opposite 10 Downing Street as the Indian PM arrived for his breakfast meeting with British Prime Minister Theresa May. They were joined by the Friends of India Society International (FISI) group, which spearheaded a crowd of Indian diaspora from across the UK waving banners such as ?Chak De India? and ?Jai Hind? outside Downing Street and nearby Parliament Square.

"We want to welcome the Indian PM to the UK and show him the diaspora support he enjoys," said one of the members of the gathering.

On the other side, the anti-Modi protesters from Caste Watch UK and South Asia Solidarity group waved banners such as 'Modi, you have blood on your hands' and 'Modi Not Welcome'.

"Hindu nationalism must be curtailed to avert India sliding towards wholesale dictatorship threatening democratic fabric, rule of law and the unity of India," a Caste Watch UK spokesperson said.

They were joined by other protestors carrying images the eight-year-old rape victim from Kathua in Jammu and Kashmir, and Gauri Lankesh, the Indian journalist who was shot at her doorstep last year.

The group also included representatives of several Indian women's groups in the UK, wearing white as part of their silent protest against 'atrocities that are taking place in India'.

"I am Hindustan, I am ashamed," read their placards alongside banners such as 'Beti Bachao' and 'Politics minus rape'.

With inputs from PTI