Armed police, riot squads and officers carrying out some stop-and-search in London would have to wear body cameras under Liberal Democrat proposals unveiled today.

The law and order reform, which will be in the party’s 2015 general election manifesto, will also require police to get a judge’s approval to carry out controversial Section 60 stop-and-searches. The existing law lets a senior officer authorise the stopping and searching of individuals in a certain area without suspicion of wrongdoing if he or she believes violence is about to erupt or that people are carrying weapons without good reason.

But civil liberty campaigners say Section 60, part of the Criminal Justice and Public Order Act 1994, has been used in a discriminatory manner, with black and Asian individuals significantly more likely to be stopped and searched.

“Far too many innocent people are subjected to stop-and-search, which is often based on crude stereotyping of minorities,” Lib-Dem Home Office minister Norman Baker told the Standard. “Stop-and-search has led to tension, and it’s something that cannot be ignored.”

Earlier this year, Home Secretary Theresa May proposed tightening rules on stop-and-search amid warnings that as many as 250,000 a year may have been illegal.

Mr Baker said mandatory body-worn cameras should be introduced across the country for armed officers, Territorial Support Group members who deal with riots and police carrying out Section 60 stop-and-searches.

His aides stressed the cameras would make it easier to investigate complaints about police behaviour, relying less on the officer’s word against the alleged victims, which would work to protect both the police and the public. The Lib-Dems are also proposing tightening the stop-and-search code of practice to focus more on known criminals or individuals matching an accurate, first description of suspects. They highlighted Equality and Human Rights Commission research last year which found that in London black people were nearly seven times more likely to be stopped than white people, mixed race individuals 2.6 times more likely and Asians twice as likely.

The Metropolitan Police is running a series of trials of body-worn cameras. Senior officers believe footage of incidents of officers responding to life-threatening and other situations will show the force’s professionalism.

They highlight the images caught by the public of armed officers overpowering the killers of drummer Lee Rigby in Woolwich last year.

The pilot scheme follows controversy over the death of Mark Duggan, 29, who was shot by Met marksmen in Tottenham in August 2011. Riots erupted in the area after the killing.

Officers, including 999 response teams, in 10 London boroughs have been equipped with 500 small cameras as part of the trial. Firearms officers will also be testing the technology.

Met Commissioner Sir Bernard Hogan-Howe believes the use of cameras will help to fight crime, defuse violent situations, lead to speedier justice and make the force more accountable.

A Met spokesman said: “Officers taking part have been given training and guidance about when cameras are to be used, which means they will routinely collect evidence in incidents such as domestic abuse and public order, but also for potentially contentious interactions such as the use of stop-and-search.”