UK riots
The Reform UK leader was told he "inflamed the rumours" about the alleged killer's identity.
The prime minister hailed the benefits of immigration in his speech to the Labour conference.
The Reform UK leader's remarks during PMQs was not welcomed by his colleagues.
"Imagine the pride we will feel as a nation when after the hard work of clearing up the mess is done".
But a quarter believe the sentences handed down to those involved are "too soft".
The far-right riots added pressure to an already tense situation in British prisons.
The Reform leader comes just behind Tommy Robinson when voters are asked who they blame for the disroder.
Christopher Steele said: "It's in very much Russia's interest to destabilise countries like Britain."
Johnson was the London mayor in 2011 when violence broke out in the capital.
The PM suggested the government may revisit its policies for online platforms after the recent riots.