For all our joking about nuclear superheroes, in 2004 AQ Khan came close to being the planet’s biggest supervillain.

In that year, Abdul Qadeer Khan, often called the father of Pakistan's nuclear weapons programme, confessed to aiding and abetting the proliferation of nuclear technology on a massive scale. Libya, Iran and North Korea were all beneficiaries of Khan’s nuclear expertise.

The full extent of his dealings has never been revealed. Khan himself recanted part of his confession and alleged the involvement of the Pakistani authorities in the transport of nuclear centrifuge equipment to North Korea.

In Pakistan Khan is seen as something of a hero and the day after his confession he was pardoned by then-President Pervez Musharraf. Khan has however since been under house arrest where the Pakistani government has refused access to the likes of the International Atomic Energy Agency who wish to fully investigate the extent and activities of Khan’s nuclear network.

And then, last week, he was freed from house arrest after the Pakistan High Court lifted the restrictions upon him. Some have expressed fears that in the years left to him – Khan is 73 and has cancer – he might try to reform his network or sell nuclear designs that may still be in his possession.

Currently, the international nuclear regime is a members only club. As long as it continues to be exclusive, more and more countries will be interested in developing nuclear energy and weapons. It’s time that the international community started cleaning their own house with a real nuclear disarmament effort.

No amount of vigilance stopped Khan giving nuclear technology to some of the worst regimes on the planet. It’s highly likely that there are other AQ Khans out there, waiting for the right opportunity and the highest bidder. As former US vice-president Al Gore once put it: ‘During my eight years in the White House, every nuclear weapons proliferation issue we dealt with was connected to a nuclear reactor program’

If nuclear power - and its so-called safe-guards - were as safe as its supporters claim, we’d have no need to worry.