Parliamentary questions and the public interest

There was an interesting discussion at the start of Question Time today about Parliamentary Questions and the public interest. Over the past two days, Pete Hodgson has been attempting to delve into the reasons for Richard Worth's sacking. John Key has consistently refused to answer because it is not in the public interest. He is entitled to do this under Standing Orders, but yesterday he went further, refusing to answer even broad questions about why he thought that answering would not be in the public interest. For example:

Hon Pete Hodgson: Does the Prime Minister judge it not in the public interest because it may hamper some police inquiry?

Hon JOHN KEY: That is possible, but also on a wider basis I do not consider it in the public interest.

Worse, he would not even indicate whether he was in possession of specific information or not:

Hon Pete Hodgson: When the Prime Minister came to the view that he had lost confidence in Dr Richard Worth, was he in possession, or not in possession, of substantive information that is not yet public?

Hon JOHN KEY: I was in possession of information that meant I no longer had confidence in Dr Worth.

In the discussion today, the Speaker indicated that whether an answer would be in the public interest or not is for the Minister to decide (which is correct), but went further to suggest that they do not need to give even the broadest outline. The problem here is that this allows (and even invites) Ministers to hide behind public interest immunity for political purposes to avoid accountability (as the Prime Minister is almost certainly doing here) - which undermines the very purpose of Question Time.

There's a clear contrast here with the provisions of the Official Information Act 1982. under the OIA, Ministers and officials may withhold information because its release is not in the public interest, but if they withhold information, they must give a reason for doing so. Better, if the applicant requests it, they must give the specific grounds supporting that reason, unless such disclosure would itself prejudice the interests in question. And they cannot withhold information concerning the existence of information except on very narrow grounds, and then only in cases covering national security, justice, or significant economic damage.

If Pete Hodgson had OIA'd the Prime Minister, he would have been entitled to reasons if no answer was given. Because he asked in Parliament, he was not. Given that Question Time in Parliament is supposed to be the primary venue by which the government and Ministers are held to account, that seems pretty odd.