Liquid containing DNA marker could assist with rapid arrests, say politicians.
A DNA marker commonly used against thieves and burglars could be pressed into action in public order situations in a move to rapidly identify suspects, it has been suggested.
During a hearing before the London Assembly, Mayor Boris Johnson said he supported exploring the deployment of Smartwater as an option available to officers.
The liquid contains a unique DNA code that can be read under special lights. It is commonly used to mark goods and equipment and as an agent to deter and identify thieves.
Mr Johnson was speaking after confirming that he would endorse a request from the Met to buy three water cannon vehicles from the German Federal Police to assist in future disorder.
He said that a poll showed that more than two-thirds of Londoners backed the move – although Assembly members opposed it, claiming the kit was costly and would be rarely used.
The purchase of the equipment must now be rubber stamped by the Home Secretary.
During the question-and-answer session with the Mayor, Assembly members highlighted that the riots of August 2011 began to abate when significant arrests were made – and suggested that Smartwater could play a role in identifying those involved in the future.
Mr Johnson told members that he supported investigating whether the liquid could be a public order tool – but warned that there were potential hurdles to overcome.
He pointed out that suspects could leave the area and could then contaminate other people with the Smartwater DNA – making it an unreliable method of identification. Mr Johnson stressed: “Smartwater could then become very dumb water.
“I have said that I am interested in the potential for Smartwater but whether that could be a replacement for water emitted at a greater pressure I do not know.”