Next month’s referendum is being held by Sikhs for Justice, which seeks independence from India and recognition from the international community of the “ongoing plight” of Sikhs there, 36 years after pogroms that resulted in tens of thousands of deaths.

The murders were precipitated by the assassination of Prime Minister Indira Gandhi. Mrs Gandhi had been responsible for Operation Bluestar, which saw a number of separatists, agitating for a separate state they call ‘Khalistan’, killed in a standoff with the Indian military.

The operation was carried out between 1 and 8 June, 1984. Militants who had taken refuge in the Golden Temple complex in Amritsar were defeated by Indian forces. It was accidentally revealed in 2014 that an SAS officer had served as an adviser to the operation, though the full extent of the Thatcher government’s involvement remains unknown.

Following Mrs Gandhi’s assassination on 31 October 1984 – by her Sikh bodyguards – mobs sought and murdered Sikhs in Delhi and elsewhere in India. The police and ruling Congress Party are widely believed to have been entirely complicit in the violence. In his book City of Djinns, William Dalrymple relates one incident in which Sikh boys in Delhi were forced to drink kerosene before being set alight.

Gurpatwant Singh Pannun, general counsel for Sikhs for Justice, said: “The Sikh people will leave no stone unturned to seek justice for the genocidal violence, but many have resolved that the only solution now is to work towards realizing our right to self-determination as guaranteed under the UN Charter.

“International law recognizes genocide and mass violence as one of the grounds for seeking independence from the perpetrating state. To this end, SFJ is holding the first ever non-governmental Punjab Independence Referendum and the voting schedule will be launched in the UK on November 18th.”