Public interest immunity is a device by which we can exclude evidence, but it can also lead to hearings with some anonymity of witnesses, to the redaction of documents and to confidentiality rings. The choice is not simply between the exclusion of material or its admissibility—evidence can become admissible through certain devices, which I shall come on to shortly if my right hon. Friend gives me time to develop my argument.
Labour, Liberal Democrat, Conservative and Cross-Bench peers agreed that the original Bill was poorly drafted and gave too much power to Ministers to decide what did or did not stay secret in court proceedings. Amendments were passed by substantial margins to put
in place what we considered to be appropriate checks and balances. No longer would the decision on whether a proceeding was held in secret be in reality taken by a Minister with the façade of a judge’s rubber-stamping it. Instead, it would be truly taken by a judge, who would be empowered to balance the public interest of holding proceedings in the open against the public interest of holding proceedings behind closed doors due to the harm done to our national security. The Lords amendments would also have ensured that the use of a CMP remained a last resort, as befits something that is anathema to open and fair justice and that, as all sides accept, should be used only in exceptional circumstances.