Scotland Yard authorised the deployment of rubber bullets ready for use on the streets of London 22 times in the past two years, The Independent can reveal.

The figure suggests the Metropolitan Police had considered ordering its officers to open fire during public disorder incidents far more frequently than previously thought. The Yard yesterday refused to say on what dates and during which situations it ordered some of the nearly 3,000 baton rounds it possesses to be distributed to firearms teams. It said the release of such information could endanger future policing operations.

The revelation that the Met authorised the distribution of the non-lethal rounds on average almost once a month in 2010 and 2011 follows the disclosure earlier this week that senior officers wanted to fire rubber bullets at rioters in south London last summer – but firearms specialists could not reach the trouble spots in time. The Met has now promised to make "more agile use" of the weapons.

Although they have been used in Northern Ireland for many years, baton rounds have never been fired on the British mainland. Even in the extreme circumstances of last August's riots their use would have been seen as a significant escalation in police tactics and a move away from Britain's consensual policing model.

The figures, obtained by the Liberal Democrat peer Dee Doocey, are an indication of an increasingly muscular response to what police believe is the increased threat to officers and the public from gangs or individuals bent on violent disorder. But campaigners argue that the use of non-lethal firearms in crowd control has no place in policing on the British mainland.

The Yard was criticised last year when it released a statement saying that baton rounds – referred to by police as attenuating energy projectiles (AEPs) – might be deployed if extreme disorder occurred during a protest in London against tuition fees.

In a written answer to a question last month from Baroness Doocey, the London Mayor, Boris Johnson, confirmed on behalf of the Met Commissioner, Bernard Hogan-Howe, that the force had "authorised the movement" of rubber bullets 22 times in 2010 and 2011. But he said details of the incidents would only be given under conditions of secrecy because, if made public, they could compromise future operations.

Lady Doocey, a member of the Greater London Authority and the Metropolitan Police Authority until it was replaced with a new body in January, said the disclosure of the precise dates was in the public interest.

She told The Independent: "I have long believed rubber bullets have no role in policing demonstrations in London. This secrecy over their potential use merely confirms that view. It is simply wrong for the Met to be silent when on so many occasions the use of rubber bullets was being considered."

Rubber bullets are designed to offer a non-lethal alternative to conventional firearms and police argue modern AEPs pose less threat of serious injury.

Between 2006 and October 2011, the Met Police bought 2,700 AEP rounds. It said it could not produce figures for baton round deployments in previous years, adding that it followed strict guidelines designed to protect life and prevent serious injury.

Opinion about rubber bullets remains divided within police ranks. A Met Police review of last summer's riots revealed officers dealing with violence in Enfield and Brixton decided against deploying the weapons because they believed it would escalate the confrontation. During the rioting, Sir Hugh Orde, president of the Association of Chief Police Officers, said he did not consider the deployment of rubber bullets in London to be sensible in "any way, shape or form".

Police armoury: Rubber bullets

The rubber bullet is Britain's contribution to the world's armoury of so-called "non-lethal" firearms.

Developed in the 1960s to replace previous projectiles such as wooden bullets, they were used widely during the Troubles in Northern Ireland.

Designed to incapacitate rioters, soldiers and police were instructed to aim below the waist. But misuse led to serious and lethal injuries.