The prime minister believes that tearing down statues is tantamount to “lying about our history” and that it is “absurd and shameful” for a monument to Winston Churchill, who is the PM’s all time favourite hero, to be boarded-up in anticipation of protests this weekend.
Scaffolding and a wooden covering was placed around the statue of Winston Churchill on Thursday evening, with the memorial in Parliament Square fenced off.
Mr Johnson said the wartime leader’s statue is “a permanent reminder of his achievement in saving this country - and the whole of Europe - from a fascist and racist tyranny.”
“We cannot now try to edit or censor our past,” he tweeted. “We cannot pretend to have a different history.”
Mr Johnson added that the “only responsible action” was to avoid planned protests this weekend.
“As for the planned demonstrations, we all understand the legitimate feelings of outrage at what happened in Minnesota and the legitimate desire to protest against discrimination,” he wrote.
“Whatever progress this country has made in fighting racism - and it has been huge - we all recognise that there is much more work to do.
“But it is clear that the protests have been sadly hijacked by extremists intent on violence. The attacks on the police and indiscriminate acts of violence which we have witnessed over the last week are intolerable and they are abhorrent.
“The only responsible course of action is to stay away from these protests.”
Black Lives Matter protests have sparked debate in the UK about the position of historical figures associated with slavery and racism.
In Bristol, protesters tore down the statue of slave trader Edward Colston while dozens of other petitions and movements have demanded the removal of other statues linked to slavery across the country.
Oxford University's statue of Cecil Rhodes has once again become a focal point of anger among protesters for his links to the slave trade.
In east London, the statue of slave owner Robert Milligan was taken down. And in Plymouth, a public square named after a 16th century slave trade is to be renamed, the city council said.
While in Poole, supporters of a controversial statue camped out overnight on Thursday to ensure the memorial was not torn down and thrown into the sea.
Scouts founder Robert Baden-Powell had expressed sympathy towards Hitler and the Nazis when he was alive but supporters of the statue say it must stay put.