Bought in 2014 from the German federal police, the vehicles have never been used because Theresa May, who was Home Secretary at the time, declined to license them citing safety concerns.
Mr Johnson and policing deputy Stephen Greenhalgh paid the German federal police almost £200,000 for the vehicles which were already approaching the end of their working life and before asking whether ministers would approve their deployment.
London’s policing watchdog has been told there are no plans to buy new, fully working water cannon following Home Secretary Theresa May’s decision to block the use of three ageing German vehicles.
Boris is forced to keep the cannon because the chances of finding someone to buy them at a price which lets City Hall and the Met cover their costs are pretty much close to nil.
In June 2014 the Mayor’s Office for Policing and Crime decided to buy three cannon from the German federal police before receiving Home Secretary Theresa May permission to deploy them.