London mayor Sadiq Khan announces sale of three secondhand water cannon that were prevented from ever being deployed

Boris Johnson’s three water cannon, bought secondhand for £200,000 when he was mayor of London, are to be sold off and the money raised will be put towards youth services, his successor has said.

The announcement by Sadiq Khan, who won the mayoralty for the Labour party in May, comes two years after Johnson bought the 25-year-old Wasserwerfer 9000 water cannon from the German federal police in anticipation of unrest on the streets of London.

At the time, Johnson insisted he had got a good deal by snapping up and refurbishing the crowd-control machinery for £218,205. But Theresa May, the home secretary, refused to allow them to be used on the British mainland.

On Thursday night Khan indicated he would fulfil his election pledge to sell the cannon.

Facebook Twitter Pinterest Sadiq Khan criticised Boris Johnson’s spending as mayor. Photograph: Brett Cove/Barcroft Images

Speaking at the State of London debate, Khan said: “One of the deals Boris Johnson managed to do with the Germans was to buy three water cannon. What I’m going to do is sell them and use the money for youth services.”

He added: “This shows the inability of Boris Johnson to get a good deal – secondhand, paid almost a quarter of a million pounds. We want to get rid of them. We are paying for storage facilities for these water cannon – that beggars belief.”

Despite Khan’s comments, a spokesperson for the mayor said no concrete steps had yet been taken to sell the cannon, which consist of a high-powered water jet mounted on top of a truck.

There was also no information on how much officials believed they could get for the now thirdhand equipment, or which youth services would benefit.

May announced in July last year that she was refusing permission for police to use water cannon against riots. She told MPs that her decision followed exhaustive medical and scientific tests that led her to conclude that they could cause serious injuries including spinal fractures.

She also said there were doubts over the usefulness of the cannon in fast-moving riots, and fears that they were likely to damage the British tradition of policing by consent. At the time, Johnson said he disagreed with May’s stance, while the Metropolitan police expressed disappointment.

On Thursday, May took the opportunity of the battle for the Conservative leadership to twist the knife again. As she launched her bid to succeed David Cameron, at which point Johnson was still believed to be in the running, she said: “Boris negotiated in Europe. I seem to remember last time he did a deal with the Germans, he came back with three nearly new water cannon.”

Water cannon have never been used on the British mainland, although they have been deployed in Northern Ireland. Calls for police to have access to them first emerged in light of the riots in 2011.