Footage appears to show a climate activist pouring human faeces on a memorial for Captain Sir Tom Moore.
The 21-year-old woman in the video - described as a former medical student called Maddie - was wearing a T-shirt that said: "End UK Private Jets."
She targeted a life-sized memorial of Sir Tom in Thistley Meadow, Derbyshire, and the clip has attracted condemnation online.
Austin Cox, who gifted the memorial to Thistley Meadow, has said: "We will be pursuing Maddie for vandalism. We will work with the police to ensure this is taken as far as possible."
In a separate video posted on a Twitter account affiliated to End UK Private Jets, Maddie said: "People are going to say that he's a hero. People are going to say that this is profoundly, obscenely disrespectful to his life and the NHS that he stood up for. And I agree.
"I was studying to become a doctor because I believe in taking care of people."
She went on to argue that the healthcare system is being forced into collapse - as well as the climate.
"We're running out of food, money, water, people to work and medicines - and meanwhile, mass death, mass disease, mass dying," she said.
The activist went on to claim that, every time a private jet takes off in the UK, "it pours a bucket of s*** and blood onto everything that Captain Tom stood for".
She appears to be from the same campaign group that disrupted the Laver Cup tennis tournament at London's O2 Arena last month.
A protester appeared to accidentally set fire to his arm ahead of Roger Federer's final professional match.
According to End UK Private Jets, the 20-year-old involved in that incident was later released from custody with a £180 fine for aggravated trespass.
This memorial of Sir Tom has been targeted before. Late last year, "IRA" was spray painted on to the sculpture.
Sir Tom, who walked 100 laps of his garden before his 100th birthday to raise more than £32m for the NHS, died in Bedford Hospital in February 2021 after testing positive for COVID-19.
He was knighted by the Queen in recognition of his efforts.