The London mayor’s office has condemned a “grotesquely irresponsible” attack in which a camera enforcing the city’s ultra-low emission zone (Ulez) was damaged with what appeared to be a homemade bomb, saying lives were put at risk. There was no immediate reaction on the incident from Downing Street or the Home Office, with No 10 saying it could not comment amid a police inquiry, but that it condemned “criminality more generally”. While the explosion in Sidcup, south-east London, on Wednesday evening is not being treated as terrorism by the Metropolitan police, counter-terror officers are leading the investigation. Photos posted on social media by people living nearby showed a large dent in a van, seemingly caused by debris from the blast, and damage to the window frame of a nearby house. No one was injured. A spokesperson for Sadiq Khan, the London mayor, said: “This grotesquely irresponsible behaviour puts both lives and property at risk. Police are rightly investigating this dangerous and reckless act.” A spokesperson for Rishi Sunak said she had seen reports of the incident but “would not want to cut across what is a live investigation”. There has been a series of vandalism incidents involving Ulez cameras since the zone was expanded to every London borough in August, a move opposed by Sunak’s government as well as Conservatives in City Hall and many Tory MPs. Figures released by the Met in November said there had been nearly 1,000 recorded crimes connected to the cameras being stolen or vandalised in the past seven months. Susan Hall, the Conservative candidate for next year’s mayoral election, and a vehement opponent of the expansion, said: “These allegations are very serious, and I fully condemn vandalism of any kind. The best way to protest against Sadiq Khan’s unfair Ulez expansion is at the ballot box next May.” A Met police statement said that a “low-sophistication improvised explosive device” damaged a camera in Willersley Avenue, Sidcup, at about 6.45pm on Wednesday. The camera had been installed earlier that day and was initially cut down before being seemingly blown up. DCS Trevor Lawry said: “It is extremely concerning that an explosive device seems to have been deliberately placed in a public place. This could have very easily resulted in members of the public being very seriously injured.” The Ulez scheme aims to improve air quality by charging a £12.50 daily fee to enter the zone for vehicles that do not meet emissions standards. It is enforced by a network of number-plate recognition cameras.