The nuclear industry in general, and Dounreay in particular, has a long history of deception.

It has an unenviable record, but we have been told many times that things are better now. We are meant to be in a new era of openness, transparency and trust.

In the light of the revelations of the last few days, this is hard to believe. In a statement to the House of Commons on Thursday, the Defence Secretary Philip Hammond disclosed that the Vulcan naval nuclear reactor near Dounreay had suffered a mishap in January 2012.

Scottish ministers, and the public, were not told about the incident until two years after it happened. Even the official safety watchdogs, the Scottish Environment Protection Agency and the Office for Nuclear Regulation, weren't told for months after the event - and were then asked by the MoD not to tell anyone else.

Worse, as we reveal today, the problem at Vulcan caused a tenfold rise in radioactive gas emissions to the environment. This directly contradicts Hammond's assurance to MPs that there had been "no measurable change in the radiation discharge" from the site.

The root of the problem lies in the MoD's historic crown immunity from regulation and prosecution. No other area of public safety policy would accept a situation in which a body responsible for some of the most dangerous nuclear activities on the planet is allowed to quietly regulate itself. Ministers must now question whether it is right for the MoD to remain outwith the law.