Police chiefs have admitted authorising the secret recording of at least one meeting involving the friend of murdered teenager Stephen Lawrence, his lawyer said on Friday.
Duwayne Brooks met Deputy Prime Minister Nick Clegg at his Whitehall office to discuss claims that the meetings were bugged.
It has been alleged that Brooks and his lawyers were invited to meetings with police in 1999 or 2000, and that officers were given authorisation to use bugs.
Duwayne Brooks, friend of murdered south London teenager Stephen Lawrence, arriving at the cabinet Office in Whitehall, central London for his meeting with Deputy Prime Minister Nick Clegg
Speaking outside Clegg's office, Brooks's lawyer Jane Deighton said evidence of the covert recording was of "immediate concern".
"We told the Deputy Prime Minister that it was untenable for any government not to do everything it could now to secure the quickest and the most thorough, and the most transparent, investigation into these allegations of police misconduct," she said.
"Duwayne was very pleased that the Deputy Prime Minister agreed that he was committed to ensuring an investigation that Duwayne himself had confidence in.
"We are going to discuss and liaise with the Deputy Prime Minister's office next week about the details of that investigation.
"But there was one matter of immediate concern to Duwayne and that's the allegations that he's had, that the police authorised the covert recording of his meetings with me and the police in my former offices. That is of immediate concern to Duwayne.
"The deputy assistant commissioner of the police has confirmed that there are documents evidencing at least one such authorisation. We believe there are more.
"We have asked the deputy assistant commissioner for the immediate disclosure of those documents.
"Those documents are ones that Duwayne really wants to see and he wants to see them now, and he sees no reason why he shouldn't see them now.
"Duwayne was also very pleased that the Deputy Prime Minister has agreed to raise the issue of the immediate disclosure of those documents with the Home Secretary."
The claims affecting Brooks came after former undercover officer Peter Francis alleged that he had been told to find information to use to smear the Lawrence family.
Eighteen-year-old Stephen was waiting for a bus with Mr Brooks when he was murdered by racists in Eltham, south-east London, in 1993.
Francis, who worked with Scotland Yard's former Special Demonstration Squad, spoke out about tactics that he said were used by the secretive unit in the 1980s and 1990s.
In the wake of his claims, Mr and Mrs Lawrence called for a public inquiry into the allegations, which the teenager's mother said made her feel "sick to the stomach".
After a meeting with Home Secretary Theresa May last week, she said: "We want it to be open and not behind closed doors, so that we can hear once and for all exactly what was going on after Stephen was murdered."
May, who previously said that two existing probes could examine the allegations, has said she will meet Mrs Lawrence again to discuss what should happen.
She initially suggested that an inquiry led by barrister Mark Ellison QC into alleged corruption in the original Lawrence murder investigation could be extended, as well as a police-led probe into the activities of undercover officers.