"The Bank of England has been assisting the SFO's criminal investigations into Libor manipulation by employees at commercial banks and brokers"
The secret recording, obtained by BBC Panorama, suggests that the Bank pressured commercial banks to push down Libor rates.
In the recording, senior Barclays manager, Mark Dearlove, instructs Libor submitter Peter Johnson to lower rates.
Dearlove says: "The bottom line is you're going to absolutely hate this... but we've had some very serious pressure from the UK government and the Bank of England about pushing our Libors lower."
Johnson seems hesitant, responding: "So I'll push them below a realistic level of where I think I can get money?"
Dearlove replies: "The fact of the matter is we've got the Bank of England, all sorts of people involved in the whole thing... I am as reluctant as you are... these guys have just turned around and said just do it."
The phone call took place on 29 October 2008, the same day that Paul Tucker, an executive director of the Bank of England, phoned Barclays boss Bob Diamond to discuss Barclays' Libor rate.
At a Treasury Select Committee hearing in 2012, both Diamond and Tucker said they had only recently become aware of Libor rigging.
Panorama played the October 2008 recording to Chris Philp MP, who sits on the Treasury committee, who responded: "It sounds to me like those people giving evidence, particularly Bob Diamond and Paul Tucker were misleading parliament, that is a contempt of parliament, it's a very serious matter and I think we need to urgently summon those individuals back before parliament to explain why it is they appear to have misled MPs. It's extremely serious."
Johnson was later sentenced to four years in prison after pleading guilty to accepting trader requests to manipulate Libor.
In response to the allegations, the Bank of England said: "Libor and other global benchmarks were not regulated in the UK or elsewhere during the period in question.
"Nonetheless, the Bank of England has been assisting the SFO's criminal investigations into Libor manipulation by employees at commercial banks and brokers by providing, on a voluntary basis, documents and records requested by the SFO."
