Hindsight is a wonderful thing. Once out of power, politicians are remarkably willing to be candid, to critically reflect whether in memoirs or interviews, in a refreshing way quite unlike the dogmatic and tribal linguistic contrivances they engage in whilst in Westminster. One subject which crops up in this way with surprising regularity is Britain's Trident nuclear weapons system.
Former Conservative Defence Minister Michael Portillo has recently described Trident as a "waste of money" which is "completely past its sell-by date", and "neither independent" nor "any sort of deterrent". Lord Des Browne, Labour's former Defence Secretary, who set the wheels in motion for Trident replacement in 2007, has now said that full replacement is 'neither strategically sound nor economically viable' and that 24-hour patrols by nuclear subs - known as Continuous At-Sea Deterrence (CASD) - should be stopped.
Even former Prime Minister Tony Blair, not known for his powers of self-criticism, has written that "the force of common sense" was against replacing Trident. He described its purpose as "non-existent in terms of military use".
So, wise when out of government, why is it that so many serving politicians seem to have an inability to grasp the argument against committing more than £100 billion to modernise our nuclear weapons.
Ahead of the parliamentary vote in 2016, when Britain will decide if it wants to remain nuclear-armed for another 30-40 years, for once, a reasoned and sensible discussion must be held. We can't wait for hindsight wisdom this time.
The government's Trident Alternatives Review, published on Tuesday, was intended to be the vehicle by which the Liberal Democrats argued against like-for-like replacement of the UK's ageing Vanguard Class nuclear-armed submarines. The Lib Dems have rightly argued that ploughing £100billion into a Cold War weapons system is untenable, especially in the current economic climate.
But while the review has challenged the doctrine of CASD and the number of submarines needed, it has fallen short (as did the government's Strategic Defence and Security Review in 2010) of looking at a non-nuclear option: scrapping Trident and cancelling its replacement.
It is right and proper that government policies should be evidence-based and considered. But in order to assess the options one cannot dismiss them out of hand.
The advantages of Britain scrapping Trident and not replacing it are clear. Helpfully, the Campaign for Nuclear Disarmament (CND) has filled in the gaps of the Trident Alternatives Review with our own report: The Real Alternative: What the Government's Trident Alternatives Review Isn't Telling You.
Strategically, senior military figures are increasingly challenging the logic of decimating the defence budget in order to maintain weapons which serve no possible purpose and only exacerbate nuclear proliferation around the world.
Economically, the commitment to spend £25billion on the 'Successor' submarines, then £3billion every year to maintain them over their lifetime, topped off with around £25bn to decommission them, is a burden which we would all have to bear. The idea that this money is best spent on an antiquated weapons system that not even the military want is bizarre.
Legally and diplomatically, becoming a non-nuclear state, as South Africa admirably achieved, would not only meet our obligations as a signatory to the nuclear Non-Proliferation Treaty, it would give us a strong and credible platform on which to challenge the spread of nuclear weapons. As things stand, our double-standards in condemning nuclear proliferation while we rearm are seen as nothing short of hypocrisy.
The UK is currently at a crossroads: we can choose to become a world leader in disarmament, non-proliferation and the verification systems necessary to realise the eradication of nuclear weapons worldwide, or we can choose to contribute to global insecurity, nuclear proliferation, and increase the risk of nuclear terrorism through the modernising of our nuclear arsenal.
To me, and to the majority of the British public, the answer is clear. Politicians need to understand it too - without waiting for the benefit of hindsight.