Undercover police officers who spied on the family of murdered teen Stephen Lawrence should be named in a new inquiry into covert policing, his mother has said.

Doreen Lawrence made the call as Home Secretary Theresa May was expected to outline the scope of the probe, set up after revelations that Scotland Yard had spied on the Labour peer's family.

Baroness Lawrence said Lord Justice Pitchford, who will lead the inquiry, should have a "presumption in favour" of naming the officers, whose identities are usually kept secret.

She told the Guardian: "For far too long, the police have had a mantra of 'we can do whatever we like'. That's what I found after Stephen's murder.

"They were doing the deception. Why should they be allowed to be anonymous while people like me had their faces all over the newspapers? These people were not innocent. They knew what they were doing."

Baroness Lawrence added she hoped the police would "speak the truth" and called for senior officers to be called to give evidence.

"I can't see how the senior officers didn't know what the junior officers were doing. The junior officers must have got their orders from somewhere," she said.

Mrs May announced her intention to set up a judge-led public inquiry after an independent review led by Mark Ellison found in March last year that the Metropolitan Police's now-defunct Special Demonstration Squad (SDS) had spied on the Lawrence family.

The Ellison report disclosed that in the late 1990s, an undercover officer - known as N81 - infiltrated a group which then sought to influence the Lawrence family campaign to further its own agenda and fed back information to his unit, including personal details such as the state of the Lawrences' marriage.

The separate police-led Operation Herne found that the SDS unit carried out undercover operations to collect information on 18 justice campaigns over the course of 35 years - including that of Jean Charles de Menezes, who was shot by police after being mistaken for a terrorist.

Set up in 1968 to infiltrate pressure groups and operational until 2008, the SDS has been the focus of intense controversy in recent years over claims that undercover officers had sexual relationships and even fathered children with campaigners to help build trust in their false identities.

The force also admitted in January this year that the identities of dead children aged up to 17 were used by SDS officers in a practice the Met conceded was "morally repugnant".

Aspiring architect Stephen, 18, was murdered by racists in Eltham in April 1993 and it took nearly 20 years for two of the gang of up to six killers to be brought to justice.