Chris Grayling apologises for monitoring of at least 32 MPs’ calls, along with some between prisoners and lawyers

Confidential telephone calls between prisoners and at least 32 current MPs or their staff have been recorded, and in some cases listened to, by prison staff, the justice secretary, Chris Grayling, has revealed.

He also disclosed that confidential calls between prisoners and their lawyers have been monitored in at least a “handful of cases”.

The chief of inspector of prisons, Nick Hardwick, has been asked to investigate the scale and extent of the problem. At least one phone call to the office of the current Liberal Democrat justice minister, Simon Hughes, has been monitored as well as five or six calls to the office of Jack Straw when he was justice secretary.

Grayling said he was only told late last week about the problem, which he said stretched from 2006 to autumn 2012 when changes were made to tighten up the system of monitoring prisoners’ phone calls.

The justice secretary apologised to the Commons for “any interception of communications between a prisoner and their constituency MP” but insisted that the “unacceptable” monitoring had been accidental rather than any intentional strategy by the prison service to listen in to calls.

He said that in 18 of the 32 cases involving existing MPs the prisoner had not listed the number as confidential and so no action had been taken to prevent the call being recorded. In a further 15 cases, the numbers were correctly identified as MPs’ offices but prison staff had failed to take the necessary action to stop them being recorded. One MP fell into both categories.

Grayling said: “I have as yet seen no evidence that information was passed on to anyone else. I don’t believe this was part of a concerted attempt to monitor. It was simply part of the routine checking of this process to make sure nothing untoward was going on. But, clearly, it’s something I’ll be asking Nick Hardwick to confirm.”

Since the changes to the phone monitoring system two years ago only calls to one MP clearly identified on prison lists had been recorded, he added. Before 2012, any prisoner who did not present a specific security risk could call any telephone number that had not already been barred from their pin account. Barred numbers included those of their victims.

The chief inspector of prisons said he would start his investigation immediately. Hardwick said: “The interception of telephone calls from prisoners to constituency MPs’ offices or other privileged communication is a very serious matter. I will begin work today to urgently review the steps the National Offender Management Service have taken to prevent this from happening in future. I will also independently investigate what has happened in the past and will report fully on the facts of what has occurred and my recommendations to the secretary of state.”

The extent of the monitoring of confidential calls has been established by an initial audit of MPs’ office phone numbers against the call records of the prisoners. No breakdown by individual prison has yet been made.

Straw, who was justice secretary from 2007 to 2010, also apologised to MPs for what had happened during his watch. He revealed that “five or six” of the monitored calls had been made to his office while he was in charge of prisons from inmates who had not identified themselves as serving prisoners.

The shadow justice secretary, Sadiq Khan, who as a solicitor had his calls from a serving prisoner intercepted, said he was “truly shocked” by the disclosure.

“There are very good reasons why correspondence between MPs and their constituents is confidential, wherever they live and whoever they are. Any breach of the long-held rules must be treated very seriously, which is why we need to get to the bottom of this urgently,” he said.

“We need to know how this was allowed to happen for so long. We need urgently reassuring that this information has not been used for inappropriate purposes, that calls between lawyers and clients aren’t also being recorded and listened into and that proper safeguards are in place to make sure there is no repeat in the future.”

Juliet Lyon of the Prison Reform Trust criticised Grayling for describing the monitoring as a “breach of protocol”. “It’s not,” she said. “It is a fundamental breach of democratic rights and justice.”