Inquiry starts after police row over use of Taser

Sir Ian Blair, the Metropolitan Police Commissioner, said the use of the Taser during the arrest on Wednesday was an "incredible risk" because it could have set off any bomb on the suspect; he stressed that was why officers were forced to shoot the Brazilian Jean Charles de Menezes, who has since been shown to be an innocent bystander, a week ago.

The West Midlands Police rejected the criticism, saying the circumstances were "very different". The force said it was voluntarily referring the use of the Taser to the Independent Police Complaints Commission (IPCC). The commission is also investigating Mr de Menezes' death.

Mr Omar, 27, a Somalian who was living in north London, is being questioned over the failed bombing at Warren Street station on 21 July .He was arrested at an address in Birmingham after a tip-off. The operation involved both forces and M15.

The Taser has been in use by British forces since last year. When fired, it sends out two darts attached to electric cables. They deliver a 50,000-volt charge, paralysing the target for several seconds.

Speaking on a BBC1 programme, Questions of Security, Sir Ian took the unusual step of criticising another force. Sir Ian said: "It was an incredible risk to use a Taser on a suicide bomber because the Taser itself could set it off and that is not the policy. I can't imagine how that was used. We use Tasers in London regularly but a Taser sends electric currents into the body of somebody; if there is a bomb on that body, then the bomb can go off."

Repeating the force's regret at the "tragic" shooting of Mr de Menezes, Sir Ian said: "Despite everything that's been said there is only one way to stop a suicide bomber, which is to kill that person because anything else that happens, unless you can persuade them in some open space to undress, everything else allows the shot to go home but the bomb to go off."

Sir Ian was backed by Robert Emerson, a former military ballistics expert. He said: "We were all surprised that they used Taser to arrest this guy. This is exactly the way not to tackle a would-be suicide bomber."

In its statement of reply, West Midlands Police said it was impossible to draw conclusions until the inquiry by the IPCC had been concluded and stressed that it believed that Sir Ian had been talking about arrests in general. It said: "Every situation in which firearms are deployed is unique. The shooting of Mr de Menezes in London and the arrest of Yasin Hassan Omar in Birmingham may appear similar but they were separate incidents."

A requiem Mass for Mr de Menezes, 27, was held at Westminster Cathedral yesterday, presided over by the Archbishop of Westminster. His funeral was held simultaneously in his home town of Gonzaga.