The second most powerful man at the Bank of England will face questions from UK lawmakers today regarding his role in the now global interest rate rigging scandal.

Paul Tucker requested the appearance just ninety minutes prior to former Barclays CEO Bob Diamond testimony last week which implicated the central bank's Deputy Governor. Diamond produced a memo sent on 29 October 2008 to his former boss, John Varley, which seemed to imply that Tucker had suggested, in a telephone conversation with Diamond, that Barclays should lower its libor submissions so as not to create the appearance of financial stress at the height of the global credit crisis.

Diamond told the Treasury Select Committee last week that he didn't take Tucker's words as an instruction, but rather an indication of concern by "senior people in Whitehall".

Treasury Select Committee members will also want to know what, if anything, Tucker and his colleagues knew of potential misdeeds in interest rate markets prior to 2008. Minutes of a Bank of England meeting in 2007 also suggest the issue of libor manipulation was discussed by Tucker and others.

Tucker will begin answering questions at 1630 BST.