The Metropolitan police were today urged to use controversial 'sound weapons' now that the home secretary has refused a license for water cannon.
The Long Range Acoustic Devices (LRADs), known as 'sound cannon', use small satellite-style dishes to emit harmful, pain-inducing sounds during riots.
The weapons can cause permanent hearing loss and severe headaches. They were held in reserve by the army during the London Olympics, but have never been used before in the UK.
Boris Johnson's policing deputy Stephen Greenhalgh was urged by Conservative assembly member Tony Arbour to purchase the weapons.
Greenhalgh said City Hall would consider purchasing the weapons.
"I would expect policing to be up to date with emerging technology," he told the London Assembly, adding that he would seek to purchase them "if there is a sound business case".
The Metropolitan police have been considering using sound weapons for a number of years.
In 2007 it was listed as one of several new weapons being considered by the force. Other weapons under consideration include 'discriminating irritant projectiles' (DIPs).
DIPs enable police to fire irritating chemicals such as CS spray at crowds from long-range. The Met began testing the weapons in 2013.
Deputy commissioner Craig Mackey told the Assembly that they would be forced to use more harmful weapons against Londoners, now the home secretary has refused a licence for water cannon.
He warned that there could be more use of plastic bullets, explaining that "you have to go up the continuum."
Both Mackey and Greenhalgh admitted that there was little chance that water cannon would ever be authorised by the current home secretary.
"[Water cannon] is not going to be an option as long as Theresa May remains as home secretary," Greenhalgh said, adding: "You cannot re-heat a soufflé. You cannot."
He said it was "an anomaly" that the home secretary was allowed to veto their use.
However, despite this veto, the police plan to hold onto the weapons in the hope that May is replaced. Greenhalgh 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 insisted.
Theresa May revealed last week that Home Office inspections had found 67 serious issues with the weapons,
The deputy commissioner refused to be drawn on why City Hall wanted to hold on to the now defunct weapons. "I'm not involved in the politics," he said.