A retired Indian army general welcomed long prison sentences handed to four Sikh extremists on Tuesday who attacked him in central London in retaliation for his leadership of a military operation against the Golden Temple of Amritsar 29 years ago.

Lieutenant General Kuldip Singh Brar, 78, had his throat slashed by a group of four in a carefully planned attack during his annual visit to London last year. Two of the attackers were jailed for 14 years on Tuesday, while two others involved in the plot received sentences of 11 and 10 years.

Lt Gen Brar has lived under tight security in India, for the last 30 years but was unprotected while on holiday in Britain. The attack was not thought to be an indication of a rising threat from Sikh extremism and was directed at continuing resentment against Lt Gen Brar.

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“They got what they deserved,” Lt Gen Brar told The Independent from his protected compound in Mumbai. “I’m sure the threat will increase with these sentences. The UK has demonstrated very clearly that it’s not prepared to tolerate terrorism on its soil.”

The retired officer said that extremist websites indicated that he had been the target of eight assassination attempts because of his leadership of the operation against militants holed up in the holiest Sikh shrine in 1984. The militants were seeking to separate from Indian rule and establish an independent state of Khalistan.

The military assault, which left at least 500 people dead, led to the revenge assassinations of Indian Prime Minister Indira Gandhi by her Sikh bodyguards, the head of the Indian army and anti-Sikh riots in that left thousands of people dead.

Commander Richard Walton, head of the Metropolitan Police counter terrorism command, said: “This was a pre-planned and organised attempt to assassinate General Brar for his military involvement in the siege of the Golden temple in India in 1984. It was ultimately unsuccessful and we are pleased that the sentencing reflects the seriousness of this attack.”