The Ministry of Defence has never been a beacon of transparency. So it was a pleasant surprise in 2010 when it was forced by a three-year freedom of information battle to release a raft of nuclear safety reports.

For the first time the public had an insight into the staffing and technical issues that plagued Trident nuclear weapons and reactor-driven submarines. For the next few years the MoD kept publishing the reports by its internal watchdog, the Defence Nuclear Safety Regulator (DNSR) – and the media kept writing stories about them. It was as if an ancient beast was at last inching out of its secretive citadel, blinking in the daylight. But it was too good to last. Last November we revealed that the reports had gone back under wraps, apparently for national security reasons.

Today we report that the MoD will not even tell us the headline summaries of the last three years’ reports. So has the DNSR given overall assurances that our nuclear weapons operations were safe, or not? We don’t know. The MoD won’t say.

This is a surreal level of secrecy. It’s fundamentally undemocratic – and dangerous. It’s symptomatic of the way the MoD sees itself: a thing apart not subject to the checks and balances normal for other bodies.

Its nuclear programme is run by military chaps, and regulated by military chaps, all from within the MoD. Having had a glimpse of this process at work, we are now back in the dark.

Regardless of what you think about Trident, this is surely unacceptable. It is about ensuring public safety by public scrutiny, and it’s our MPs who need to act. They must try and drag the MoD back out of its citadel, kicking and screaming if need be.