SIR Nicholas was responsible for advising the prosecution of the Matrix Churchill defendants and persuaded four ministers to sign Public Interest Immunity certificates which prevented the disclosure of government documents that were crucial to the defence.
However, the trial judge overruled the decision and the case collapsed.
All the ministers willingly signed, except the deputy prime minister, Mr Michael Heseltine, who expressed his concern to Sir Nicholas that "no rational person" would think the documents should not be disclosed. He initially refused to sign the PII certificate but reluctantly agreed after warning that it would appear to the public that ministers were engaged in a "cover up".
Sir Nicholas admitted to the Scott inquiry that he had not read all the documents which he wanted covered by the PII certificates. He has repeatedly insisted that he will not resign and that he acted "scrupulously and with complete integrity" throughout the Matrix Churchill affair.