The white anti-apartheid activists trusted Vanessa Brereton as one of their own - a lawyer fighting for those involved in the struggle. But all along she was spying on them for the security police.

On Tuesday, after her confession that it was she who was agent RS452 - and not Scorpions boss Bulelani Ngcuka - her old comrades told of their shock and anger at the way she had betrayed them, even while defending activists in court.

Brereton, a former Port Elizabeth human rights lawyer who now lives in the United Kingdom, has lived for years with guilt and self-loathing over her double life.

When the Ngcuka spy allegations blew up, she decided to come clean.

Her former handler, Bureau for State Security (Boss) Agent R1653, Karl Edwards, confirmed on Tuesday that Brereton was RS452, the codename bandied about in spy accusations against Scorpions chief Ngcuka.

"I am terribly shocked," Edwards said from Port Elizabeth. "I did not really expect her to confess and all along I was protecting her identity.

"We are both just caught up in a fight between (Deputy President Jacob) Zuma and Ngcuka, but I had no intention of telling the Hefer Commission who the real RS452 was."

Mac Maharaj, African National Congress stalwart and former minister of transport, who first confirmed the suspicions against Ngcuka, said: "Well, things are getting more and more interesting.

"All I want to say at this stage is that I will be going to the commission as arranged on November 17."

The commission resumes in Bloemfontein on Wednesday after a five-day break for further investigations, as it sought "truck-loads" of secret files deemed crucial to the allegations.

Over several days last week, Brereton told of the double life that had left her feeling sullied - and in fear.

Suspicions against Brereton, then unnamed, were raised when Ngcuka's office countered claims in a Sunday newspaper that he was a spy.

He said agent RS452 was a white woman from the Port Elizabeth area.

Information leaked to the media placed the woman at a meeting in 1989 with nine anti-apartheid activists in the city, which led to a raid on offices and homes.

Janet Cherry, then a banned activist and now a Human Sciences Research Council researcher, said Brereton had fitted the description.

"I am shocked, but not surprised, but also very sad."

She said she felt betrayed by someone who had represented her and other activists against security police several times.

Brereton appeared for the defence in numerous political trials in the turbulent 1980s and won a reputation as a fighter for the rights of the oppressed.

But throughout that period and until April 1991, she was an undercover member of the security police.

Another activist present at the 1989 meeting, Glenn Goosen, himself a human rights lawyer, said the implications for a lawyer who worked for an agency she fought on behalf of her clients were "quite serious".

"Her practice was entirely built on left-wing cases," he said. "Personally, it is still difficult to come to terms with that level of betrayal."

Now living a quiet suburban life outside London, Brereton is preparing an affidavit for the Hefer probe.

It will give details of her recruitment as an informer in 1985 and an undercover police constable a year later, with the designation RS452.

This was part of Operation Crocus, a security police project aimed at infiltrating and collecting information about the "white left".

Edwards recruited Brereton, an anti-communist, to spy on people such as Cherry and Molly Blackburn, who has since died.

Brereton gave Edwards reports of meetings of the "white left".

Blackburn's sister, ANC MP Judy Chalmers, said on Tuesday morning that Brereton had offered her help to activist groups such as the Black Sash in the wake of the 1985 Langa massacre.

"We were at that stage very happy to have help, because shortly afterwards, more sinister incidents happened."

Of Brereton, she recalled: "She did not have many social skills. She was disabled and often in pain, but she seemed like a caring person and probably was. I don't think anybody at the time really doubted her integrity, despite the fact that she obviously had money."

Brereton admits enjoying the attention and the accolades of security police. But she also began to have doubts about the people she spied for.

At first she had been prepared to believe the promises of security police she was in contact with that they and their colleagues were not involved in anything brutal.

The turning point came in 1989 with the killing of three black security police officer and an askari.

They were blown up by a bomb attached to their car in Motherwell and which was detonated by Niewoudt.

With acknowledgements to Christelle Terreblanche, Terry Bell and the Cape Argus.