Boris Johnson considering buying 'sound cannons' to help Scotland Yard tackle riots

Water cannons have been banned after more than £200,000 was spent on them

London Mayor Boris Johnson wants to purchase LRADs to help police deal with rioting (Getty Images)

Boris Johnson may consider buying controversial “sound weapons” for Scotland Yard to use when dealing with riots – despite the risk they can cause permanent hearing loss.

The Mayor of London’s policing deputy Stephen Greenhalgh said City Hall would seek to purchase the Long Range Acoustic Devices (LRADs) “if there is a sound business case”.

After being urged to purchase the weapons he told the London Assembly on Tuesday: “I would expect policing to be up to date with emerging technology.”

LRADs, known as “sound cannons”, use small satellite-style dishes to emit harmful, pain-inducing sounds during riots and can also cause severe headaches. The weapons were held in reserve by the army during the London Olympics, but have never been used before in the UK.

The announcement comes after Mr Johnson was humiliated in the Commons last week by Home Secretary Theresa May, who banned the use of water cannons despite the Mayor having already spent more than £200,000 on three of them. She said inspectors had found 67 faults with the former German federal police vehicles.

Met Deputy Commissioner Craig Mackey told the Assembly that as a result of Ms May’s decision police would be forced to use more harmful weapons against Londoners. He warned that there could be more use of plastic bullets because “you have to go up the continuum”.

Mr Greenhalgh said it was “an anomaly” that the home secretary was allowed to veto the use of water canon and claimed the second-hand cannon would remain “mechanically operational” for up to ten years.

“The idea that these are 25-year old rust-buckets is simply untrue,” he said.