Two mothers whose sons were stabbed to death in the same year have taken their campaign for peace to a school in East London.
Jimmy Mizzen and David Idowu were both murdered in 2008.
Their mothers have spent 100 days touring the capital speaking to young people about avoiding violent confrontations.
Their project will end with a concert on Sunday.
More top news
The number of people allowed into official spectator areas will be cut by a fifth with just 100,000 tickets available.
The mayor was being challenged by Labour following his selection as the Tory candidate for the safe seat of Uxbridge and South Ruislip.
Puffin was found hobbling around a housing estate with his fur full of rubbish and faeces.