Soldiers were heckled by protesters as they silently cleaned graffiti off a war memorial after a Black Lives Matter demonstration.
The Grade II listed Earl Haig Memorial in Whitehall, London, was sprayed with the letters 'ACAB', meaning 'All cops are b******s'.
The young troops, stationed at the Household Cavalry's barracks nearby, volunteered to clean the writing off the base of the statue.
In a video of the encounter, one woman can be heard hammering the squaddies for 'not even waiting a day' before wiping away the vandalism.
She also mocked them for protecting their 'precious memorial' while filming them hard at work.
Earlier in the clip another woman said: "Excuse me, when I saw you earlier you all picked up signs and put them in bin bags.
"Why did you pick them up? I don't understand."
The Black Lives Matter protest in London on Wednesday was largely peaceful, unlike some of the demonstrations in the US, where scenes of looting and arson have been filmed.
Protests have been held across the world in response to the killing of African American George Floyd.
Mr Floyd died after a policeman knelt on his neck for almost nine minutes.
The Earl Haig Memorial consists of a bronze statue of World War One Field Marshal Douglas Haig, later made an earl, on a horse.
He was nicknamed 'Butcher Haig' due to the huge number of casualties under his command, including almost 20,000 deaths on the first day of the Battle of the Somme.
Today people went down on one knee for an anti-racism protest in London's Trafalgar Square despite police warning that such mass demonstrations could be viewed as unlawful.
Those who took part in the tribute to George Floyd, who died at the hands of US police, knelt two metres apart in the shadow of Nelson's Column, wore masks and carried homemade placards which condemned racism and brutality.
A placard held by a black woman read: "I am human that is enough."
Other banners held by the protesters, who came from different races, also said "white people must do more", "colour is not a crime" and "no justice no peace prosecute the police".
Deputy Assistant Commissioner Laurence Taylor earlier said that such protests should not take place under current coronavirus restrictions.
