Undercover police operations could not be launched without a judge's approval under a Labour government, the party has announced amid an inquiry into spying.
Diane Abbott unveiled the policy during her speech to Labour’s annual conference in Liverpool.
“We know that in this country you generally need a warrant to enter someone’s home or intercept their telephone calls,” the shadow home secretary was to say.
“We will insist on time-limited, judicial warrants for any undercover policing.”
Telephone interceptions are currently subject to warrants from the home or foreign secretaries, and magistrates give permission for property searches in most cases.
But police forces themselves govern the placement of undercover officers and there are mounting calls for more transparent oversight.
A Labour spokesperson said its proposal was a response to “gross violations” of privacy and human rights in undercover operations, including police officers having sexual relationships and children with the activists they targeted.
The Metropolitan Police issued an apology to women tricked into relationships in 2015 and has paid some victims compensation for the “abuse of police power” by officers who infiltrated protest groups.
The scandal erupted after Mark Kennedy, an undercover spy who infiltrated environmental groups for years, was unmasked by activists in 2010 and Theresa May ordered a judge-led public inquiry as home secretary.
Led by Sir John Mitting, it is probing investigations by police forces in England and Wales since 1968 and will look at officers’ actions, their training and supervision, and make any recommendations about changes to the law or practice in future.
Last week, legal papers served in a separate case revealed that Kennedy’s managers knew he had deceived an environmental campaigner into a relationship and let it continue.
Kate Wilson, who launched a claim in the Investigatory Powers Tribunal, said senior officers had “sanctioned the systematic violation of human rights because of political beliefs, and we still don’t have the whole truth”.
She is one of eight women who brought a case against the police over undercover relationships,m while the Undercover Policing Inquiry is also investigating the use of dead children’s identities by officers.
On Thursday, a former police spy known as HN16 was revealed to sometimes have used the name Kevin Crossland when deployed into the Animal Liberation Front and the Brixton and Croydon Hunt Saboteurs between 1997 and 2002.
Kevin Crossland was the identity of a deceased child who died in a plane crash in 1966 and the inquiry is calling for evidence on why and how the name came to be used, without being sanctioned by the Special Demonstration Squad.
Kevin’s family said the five-year-old was “very happy” and “full of life” when he died while journeying to from Luton Airport to Ljubljana.
Their plane crashed shortly before coming into land, with Kevin, his sister and mother killed while the boy’s father survived with “multiple injuries, burns and enormous guilt that he was not able to save his family”.
The ongoing inquiry will look at the work of the Special Demonstration Squad, the National Public Order Intelligence Unit and all police forces in England and Wales, examining whether people may have been wrongly convicted in cases involving undercover officers.
It will address claims Scotland Yard spied on campaigners fighting for justice for murdered teenager Stephen Lawrence, and the infiltration of unions and other organisations.