The former Mayor of London has come under fire after water cannons he bought – which were declared unfit for use – were sold for scrap at a loss of £300,000.

The three cannons, which would have been used as crowd control weapons, were bought in 2014 by the former Mayor of London, Boris Johnson – despite being illegal in the UK at the time.

They were put into storage when Theresa May refused permission for their use in London in July 2015.

But the cost of buying and updating the machines cost Mr Johnson more than £322,000, and were sold yesterday (19) for just £11, 000.

The water cannons have been sold by the current Mayor of London, Sadiq Khan, despite being up for sale since 2016.

Mr Khan said: “For too long, London taxpayers have had to bear the brunt of Boris Johnson’s appalling botched water cannon deal. This has been another waste of taxpayers’ money by Boris Johnson. Londoners continue to live with his vanity.

“I am pleased we have managed to finally get rid of them and I made an election promise to Londoners that I would claw back as much of this cash as possible and pump it into helping young people at risk of being affected by crime and giving them better life opportunities.”

Mr Khan now plans to use the money to invest in his Young Londoners Fund which supports community organisations working with young people at risk of getting caught up in crime.

He will be funding 72 new projects across London and has now invested £20.5 million so far this year in the Young Londoners Fund.

Mr Khan added: “By working with communities and giving young Londoners meaningful things to do, I am doing everything I possibly can to help ensure they make the right choices and do not follow the wrong path at such an important time in their lives.”

Other London politicians were also quick to criticise Boris Johnson.

Green party London Assembly member, Sian Berry, tweeted: “Final proof that Boris’ water cannon stunt was just money down the drain. It’s an affront to Londoners that any public money was spent on what is essentially a weapon again the people.”

Liberal Democrat London Assembly member also asked Mr Johnson whether he would be meeting his long-standing pledge to be blasted by a water cannon – something he promised in 2014 to reassure people of their safety.