The undercover officer behind claims that police moles were told to smear the family of murdered teenager Stephen Lawrence has been denied immunity from prosecution.
Peter Francis was told by Steve Craddock from Derbyshire Police that no such protection could be offered, in return for his co-operation with an investigation into Scotland Yard's Special Demonstration Squad.
Mr Francis told Channel 4 News that without the guarantee, he will only give evidence to a public inquiry about his explosive claims, or to the Home Affairs Select Committee.
The development re-ignited questions over police records that contain references to officers being deployed to look at groups supporting the Lawrence family.
Baroness Lawrence's solicitor Imran Khan told the broadcaster that Scotland Yard had told the family that officers had looked at supporters of their justice campaign. He said: "They confirmed that their records indicated that what Peter Francis is saying is accurate. Records indicate that undercover officers were deployed to look into campaigners and supporters of the Lawrence campaign, Lawrence family."
However the force stressed that no evidence had been found to back the smear claims. A police investigation into the activities of undercover officers from Scotland Yard's Special Demonstration Squad is currently under way, called Operation Herne.
The force said in a statement: "It is absolutely incorrect to say that the investigation has uncovered evidence that undercover officers were deployed to smear the Lawrence family. Although Operation Herne is ongoing, to date no evidence has been found that supports this very serious allegation."
It released a section of a letter to Mrs Lawrence that was sent following a meeting with Metropolitan Police commissioner Sir Bernard Hogan-Howe.
The excerpt read: "Records exist which indicate that undercover officers were deployed into supporters and campaigns connected with Stephen's family. At this time we are unable to verify his (Peter Francis) other allegations but records continue to be searched and therefore this position may change.
"In July chief constable Mick Creedon, who is leading an inquiry into the activities of Scotland Yard's undercover Special Demonstration Squad, said that he had found no evidence to back the smear campaign. He revealed that references had been found to undercover officers looking into protest groups that might target the Stephen Lawrence justice campaign, but nothing to suggest attempts to 'besmirch' the family.
But Mr Francis is standing by his claims. He said if Mr Creedon does not uncover proof, then a public inquiry into what happened may do so.