The ex-police officer at the centre of the row over the bugging of an MP claims he was asked to listen to a second legally privileged conversation.
Mr Kearney was an intelligence officer at Woodhill Prison
Mark Kearney says he was asked to eavesdrop on a conversation between a terror suspect and his solicitor during a visit at Woodhill Prison.
He makes the allegations in documents obtained by the BBC's Newsnight.
He also says he was pressurised by the Metropolitan Police to bug MP Sadiq Khan when he met a constituent.
The former police intelligence officer at the Milton Keynes prison said he was put under pressure by a West Midlands police officer to listen to the second conversation.
The prisoner was not actually at Woodhill at the time, but the police officer wanted to know if he could be transferred there so the recording could take place.
The detailed documents, obtained by BBC East home affairs correspondent Sally Chidzoy, were prepared for an unrelated case in which he is fighting allegations of leaking information to a local newspaper.
Mr Kearney said he told the West Midlands officer he was unhappy at being asked to record conversations between a solicitor and client, which he knew were legally privileged.
He said: "I told him that we, as an establishment, would be reluctant to carry out such work. The consequences of discovery would undermine the whole legal visits process."
The document also details his claim he was pressured to bug the meeting between Tooting MP Sadiq Khan and his constituent Babar Ahmad.
Mr Ahmad is fighting deportation to the US on charges of raising funds for terror groups.
Mr Kearney said he "came under significant pressure from the Metropolitan Police requesting that we covertly record a social visit between a (suspected) terrorist detainee and an MP". "This was authorised by the Metropolitan Police," he added.
"This request was very difficult. The MP concerned was Sadiq Khan, the member for Tooting. Mr Khan is a prominent human rights lawyer. This concerned me on the grounds that the recording may cross the barriers of legal privilege."
Mr Kearney also says he was asked by the Serious Organised Crime Agency to allow access to a woman's handbag when she visited a 'Category A' prisoner.
He said he consulted the prison's deputy governor on the matter and they allowed it to happen twice despite being very reluctant to do so.
Mr Kearney said the governor "conceded that it was necessary but left me in no doubt that if there was a compromise, then it would be my responsibility.
"Items such as keys, sim cards and financial paperwork were copied whilst the visits took place".