The climate demonstrators – among them a Northern Ireland veteran – unveiled a banner reading “Honour Their Sacrifice, Climate Change Means War” at the war memorial on Whitehall in central London on Wednesday.
The British Legion responded by stressing that Armistice Day was “a time for remembrance, and not for political protest”. And Labour has now added to the criticism.
Starmer’s approach marks a shift from his predecessor Jeremy Corbyn, who praised XR for past protests.
A spokesperson for Starmer told reporters: “Today is Armistice Day when the whole country is remembering the sacrifices of those men and women who have fought for our freedoms.
“No one can doubt how serious the climate emergency is.
“But the protests at the cenotaph are wrong. They’re in bad taste and we do not support them.”
Boris Johnson also condemned the protest.
A spokesperson for the prime minister said: “The cenotaph is a memorial to those who fought and died to preserve all our freedoms.
“On today of all days, when we joined together to pay tribute to our war dead, this action was profoundly disrespectful.”
After the banner was displayed, British Army veteran and Extinction Rebellion member Donald Bell observed a two-minute silence before hanging a wreath of poppies bearing the message: “Act now.”
Bell, 64, who completed four tours in Northern Ireland during the Troubles, said: “Unchecked climate change means a return to a world at war.
“I took action today knowing that I would be criticised.
“I knew that I would be accused of being disrespectful and hated by many for speaking out in this way. Remembrance Day is never an easy time for veterans and this was not an easy decision for me to make.
“This government’s own climate advisers, the committee on climate change, said last year that they have a ‘Dad’s Army’ approach to protecting British people from the impacts of climate change.
“Their report in June this year showed that the government has failed to meet all but two of the 31 milestones it set itself for reducing emissions.
“This government is criminally negligent and young people today will pay the price for their failure.”
A Royal British Legion spokesperson said: “War memorials and graves honour the memory of every member of the armed forces who has made the ultimate sacrifice and deserve to be treated with the utmost respect.
“The armed forces community, past and present, have made sacrifices in defence of the freedoms we have today, including the freedom of speech.
“While we respect the right of others to express their opinions within the law, we believe the Poppy Appeal is a time for remembrance, and not for political protest.”