Mr Malthouse said: “The policy of the Met Police is very clear. The public have the right to be able to identify any uniformed police officer and so badges should be worn at all times. We support the Commissioner's decision to hold officers to account when they purposely conceal their identity.”
The Home Office also criticised officers who fail to wear their epaulettes, insisting the “public has a right to be able to identify” them.
A Home Office spokesman said: “We welcome the Commissioner's statement that all uniformed police officers should be identifiable at all times by their shoulder identification numbers, and wholly agree that the public has a right to be able to identify any uniformed officers while performing their duties.”
A Yard spokesman said: “Where provided, epaulettes with identifying letters and numerals or insignia of rank must be worn and must be correct and visible at all times.
“It is the responsibility of all police officers, and their supervisors, to ensure this policy is followed.”
But there was no statement from the commissioner, who is now facing a mounting crisis over his leadership.
A member of the Metropolitan Police Authority said the problem of officers failing to wear their shoulder numbers had been going on “for some time” and “serious questions” will be raised over the issue.
Cindy Butts said: “I see no good reason why they should obscure their numbers from members of the public.
“We have pushed for the Met to have officers wear their names on their uniforms so at the very least they should be wearing the shoulder numbers.”
She added: “This has been an issue that's been going on for some time. The Met need to explain why this is happening and I certainly will be putting those questions to them.”
Today there were calls for the officer's immediate suspension and more questions over Sir Paul's leadership of the force, already engulfed in crisis since the death of Ian Tomlinson, 47, who had a heart attack during the G20 riots after being pushed and struck with a baton by a masked officer.
Senior politicians warned there is no place in Britain for “secret police”.
Shadow home secretary Chris Grayling said: “The police just can't take their numbers off because they are in difficult policing situations. In the end, if there are complaints, it will just make matters worse for them.”
Liberal Democrat home affairs spokesman Chris Huhne added: “Sir Paul Stephenson has made it clear that no British officer should be ashamed of their uniform or their identification. It now looks as if his orders are being flouted. There is no place for secret police in Britain.”