Lord Justice Leveson will use the resumption of his inquiry next week to question the Mail on Sunday. The move follows claims made by the Associated title last week that the judge "threatened" to resign four months ago unless Downing Street offered new assurances that the inquiry team was not wasting its time.
The opening period of Monday's session at the Royal Courts of Justice is on course to be one of the most politically heated sessions so far.
Associated's leading counsel, Jonathan Caplan QC, is expected mount a defence of the MoS article, with Leveson equally determined to assert his inquiry's independence from political interference.
Core participants, including phone-hacking victims, national newspaper groups and the Metropolitan Police, have all been asked for their comments on the MoS story. Last night, the paper's editor, Geordie Greig, told The Independent: "I cannot comment further on this, however we stand by the contents of our story."
The MoS said that a speech by the Education Secretary, Michael Gove, to parliamentary journalists in February, in which he said the Leveson Inquiry was having a "chilling effect" on press freedom, prompted the judge to contact the Cabinet Secretary, Sir Jeremy Heywood.