It is “absurd and shameful” that a statue of Winston Churchill has had to be boarded up because of fears it could be vandalised, the prime minister says.
Boris Johnson said the war-time leader had expressed opinions which were “unacceptable to us today” but remained a hero for saving the country from “fascist and racist tyranny”.
Protesters daubed “was a racist” on the monument last weekend.
Mr Johnson also urged people not to gather amid the coronavirus pandemic.
In a series of tweets, he said: “We cannot now try to edit or censor our past,” adding that such monuments were put up by previous generations.
It comes after the statue of slave trader Edward Colston was thrown into the river in Bristol during a Black Lives Matter protest on Sunday.
Demonstrations have been taking place across the world following the death of George Floyd in Minneapolis after a police officer held a knee on his neck for nearly nine minutes.
Mr Johnson said that, while he understood “legitimate feelings of outrage” at what had happened, the “only responsible course of action” was to “stay away from these protests”.
They had been “hijacked by extremists intent on violence”, he said.