The British government had released figures stating that 379 innocent people had died while 1,200 were wounded in the brutal tragedy. (Photo: AP)

London: Falling short of a complete apology, British Prime Minister Theresa May on Wednesday said the UK "deeply regrets" the 1919 Jallianwala Bagh massacre and called it a "shameful scar" on the British-Indian history.

"The tragedy of Jallianwalla Bagh in 1919 is a shameful scar on the British-Indian history. As her Majesty, the Queen said before visiting Jallianwala Bagh 1997, it is a distressing example of our past history with India. We deeply regret what happened and the suffering caused," May said at the British Parliament.

Hundred years on, the United Kingdom is yet to give a full apology for the gruesome attack on unarmed protesters in Amritsar in 1919.

Highlighting this, Opposition leader Jeremy Corbyn said: "I think the people, in memory of those who lost their lives in the brutality of what happened, deserve a full, clear and unequivocal apology for what took place on that occasion."

The Jallianwala Bagh massacre took place on 13 April 1919 when troops of the British Indian Army under the command of Colonel Reginald Dyer fired machine guns into a crowd of unarmed protesters, along with Baishakhi pilgrims, who had gathered in Jallianwala Bagh, Amritsar, Punjab.

The British government had released figures stating that 379 innocent people had died while 1,200 were wounded in the brutal tragedy.

The British Foreign Secretary, Jeremy Hunt, outlined that the "passage of a century" cannot "wipe away the stain of lost lives" in the massacre. "Churchill called it monstrous, David Cameron said it was shameful. It was both - one of the most appalling episodes in British history. The passage of a century will not wipe away the stain of innocent lives being taken at the Amritsar massacre," he tweeted on Wednesday.

May, during the Prime Minister's Questions in the House of Commons, also highlighted current India-UK relations.

"I am pleased that today the India-UK relation is one of collaboration, partnership, prosperity and security. Indian diaspora make an enormous contribution to British society and I'm sure that the whole House wishes to see the UK's relationship with India continue to flourish," she said.