To conspire - "to combine secretly for an unlawful or wrongful act".
In a way, John Purdey is right, but not in the way he thinks.
Remove the word “secretly” and you have the perfect description of the actions of many involved in maintaining the airworthiness of the Mk1, and attaining the airworthiness of the Mk2.
Bottom line – they avoided an obligation to the Secretary of State for Defence by knowingly compromising airworthiness in the years before and after Mull. And, John, to address one of your questions, the current SofS is aware of this, and content.
In their supreme arrogance, MoD does not deny this, but flaunts it. (And, as I said, CDP said as much to the HCDC when asked specifically about Chinook). But, case by case, they are being exposed and losing in the courts. Nimrod. C130. Next…………?