Video report by ITV News Correspondent Sejal Karia

The UK envoy to India has said Britain regrets a massacre of hundreds of Indians by colonial forces in the north-west city of Amritsar 100 years ago, and “will continue to do so”.

British High Commissioner Dominic Asquith said "you cannot rewrite history" as he stopped short of an apology.

Saturday marks the centenary of the attack at Jallianwala Bagh by British colonial troops on unarmed Indians attending a peaceful rally calling for independence.

More than 300 Indians were killed and 1,200 injured during the massacre, which galvanised the national independence movement.

A ceremony marked the 100th anniversary of the massacre. Credit: AP

Mr Asquith said “the revulsion that we felt at the time is still strong today”, as he paid tributes at the Jallianwala Bagh memorial in Amritsar.

He added: "It tarnished the reputation and we regret, as I say, the suffering and we'll continue to do so.

"The suffering caused…You might want to rewrite history, as the Queen said. But you can't."

But on Saturday, Labour shadow home secretary Diane Abbott tweeted it was time for Britain to "face up to its past" and apologise.

Earlier this week, Prime Minister Theresa May called the killings a “shameful scar” in British-Indian history, but stopped short of formally apologising.

A debate in the Commons earlier this week, initiated by Conservative MP Bob Blackman, discussed the Jallianwala Bagh massacre.

Mr Blackman called on the government to formally apologise ahead of the centenary this Saturday, adding that the "time was right".

In 2013, David Cameron became the first British Prime Minister to visit the scene of the massacre but offered no formal apology.

Mr Cameron said at the time: "In my view, we are dealing with something here that happened a good 40 years before I was even born, and which Winston Churchill described as 'monstrous' at the time and the British government rightly condemned at the time.

"So I don't think the right thing is to reach back into history and to seek out things you can apologise for."