GO 20 was launched today in Islington, London's first 20mph borough.
Children heard from Paralympian Danny Crates on how great it is to be active, took part in a safe cycling demo with Islington Council, carried out speed checks on traffic with help from the Met and celebrated 20mph by displaying their own banners and placards.
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It is the fourth time in five years that the London borough has topped the rankings, according to data from the ONS.
Catherine Burke's body was discovered at a house in a quiet street in Muswell Hill last Thursday evening.
Residents said living next to the 40 foot high stinking mound was a 'living nightmare'.