By Estelle Shirbon
LONDON (Reuters) - London Mayor Sadiq Khan has put up for sale three water cannon that were bought in 2014 by his predecessor Boris Johnson but never used, because the government refused permission for police to use them.
The decision to sell the cannon, which cost in total over 322,800 pounds ($410,000) to buy, refit and maintain, prolongs a humiliation originally inflicted on Johnson, now foreign secretary, by fellow Conservative Theresa May, now prime minister.
Johnson bought the second-hand cannon from Germany arguing they could help prevent a repeat of riots that broke out in London in 2011, but May, then interior minister, refused to allow their use anywhere in England or Wales.
Water cannon have been used in Northern Ireland but not elsewhere in the United Kingdom.
May told parliament last year her concerns included the risk of injuries, the cannons' limitations in dealing with riots, and the potential damage to police legitimacy in the eyes of the public.
Khan, who is from the opposition Labour Party, said proceeds from the sale would go towards tackling gang crime.
He issued a detailed breakdown of the money spent on the cannon, ranging from the purchase price of 85,000 pounds to repainting costs of 19,000 pounds and the fitting of CD players for 970 pounds.
"It beggars belief that such a huge amount of taxpayers' money has been wasted on paying to store these redundant machines," Khan said in a statement, blaming Johnson for acting "rashly" in purchasing them.
Johnson's office did not immediately return a call requesting comment.
May's decision to block the use of Johnson's cannon was an early skirmish in a relationship that has remained volatile.
Launching her campaign to be prime minister on June 30 this year, May referred back to the episode to make fun of Johnson, then considered a potential rival for the job.
"Last time he did a deal with the Germans he came back with three nearly-new water cannon," she said to laughter.
She later surprised everyone by appointing Johnson her foreign secretary, but it has not all been plain sailing. Last week, she slapped him down after he said Saudi Arabia was stoking proxy wars in the Middle East, a comment at odds with Britain's official line.
This week, Johnson got his own back by comparing a pair of expensive leather trousers worn by May to rather less fashionable traditional German leather shorts.
"We are so cosmopolitan that ... our wonderful prime minister actually wears lederhosen," he said.
(Editing by Stephen Addison)