As of earlier this year, the veto described as a constitutional aberration by the Lord Chief Justice had only been used six times, including to block the release of the Attorney Generals legal advice on the Iraq war and to halt publication of the Prince of Waless private letters to ministers.
The report also foreshadowed the projects major difficulties in keeping control over its budget, saying not enough work had been done to bottom out the projects true costs and affordability. Since the report was written, HS2s overall budget has risen by about a third, from £32 billion to £43 billion at 2011 prices.
The document was cleared for release by the Information Commissioner in June, but the Government was due to lodge an appeal to the Information Tribunal last Thursday. That hearing was adjourned at the last minute after Patrick McLoughlin, the Transport Secretary, and Francis Maude, the Cabinet Office minister, wrote to Mr Cameron warning that the Government was very likely to lose and it would be better to veto now than after an adverse tribunal decision.
Justifying the exceptional use of the veto, the ministers said the publication of the report would create political and presentational difficulties at a crucial point in the HS2 projects development