In the aftermath of the 2011 London riots police suggested the use of water cannon, as seen in this file photo, to deal with future social unrest.
London CNN  — 

Three water cannon bought and refurbished by former London Mayor Boris Johnson at a cost of hundreds of thousands of dollars have been sold by his successor to a scrap yard for just over $14,000.

Johnson – who is now a member of parliament in the governing Conservative party and was Britain’s foreign secretary until July – bought the secondhand crowd dispersal vehicles from the German police for around $109,000, following riots in London in 2011. He then spent a further $305,000 refurbishing them.

But he failed to secure permission to use the cannon, the Mayor of London’s office said in a statement Monday.

In 2015, Theresa May – now Prime Minister but at the time the minister in charge of policing – refused to authorize their use, a move that was seen as a snub to Johnson. For the past four years, the cannon have been languishing unused in storage.

The mayor’s office said Monday that the vehicles were sold to scrap metal yard Reclamations (Ollerton) Ltd. in the north of England.

The proceeds of the sale, which will be used to fund youth projects, amount to around 3.5% of the nearly $414,000 spent on buying, refurbishing and maintaining the vehicles since 2014, according to figures released by the mayor’s office.

Roadworthy

The controversial cannon were extensively refurbished to become roadworthy – the work included body repairs, security camera installation and around $41,000 to make sure the vehicles complied with London’s low emission zone.

“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,” current London Mayor Sadiq Khan, who is in the opposition Labour Party, said in a statement.

Johnson has yet to reply to CNN’s request for comment.

‘Waste of money’

Liberal Democrat London Assembly member Caroline Pidgeon said on Twitter that the sale of the cannon at a loss reflected the “true cost for Londoners of Boris Johnson’s foolish policies.”

Sian Berry, assembly member and joint leader of the Green Party, called the cannon on Twitter a “weapon against the people” and a waste of money.

In 2011, riots spread across English towns and cities after the fatal police shooting of Mark Duggan in north London.

In the aftermath, police suggested water cannon and plastic bullets to deal with future social unrest.

A YouGov poll found in 2014 that 68% of British people thought police should be able to use water cannon during riots. And 26% said they would pay to see them used on Johnson.