President Obama's recent Berlin speech has raised the profile of nuclear disarmament once again, pledging a number of useful advances. But he didn't quite take us to the dizzy heights of hope and emotion stirred by his Prague speech in 2009 . And maybe that's because since then we've seen that whatever his intentions, he has been unable to deliver on his disarmament promises without at the same time pledging modernisation of nuclear weaponry and pursuing new systems which render void the 'deterrent' effect of his potential opponents' nuclear weapons.

All too frequently we find that policies run on contradictory lines. The same applies to UK policy with regard to nuclear weapons. Since 1968, the UK has been explicitly committed to multilateral nuclear disarmament, through its backing for the nuclear Non-Proliferation Treaty . Yet during this period it has retained and upgraded its nuclear weapons capacity and has failed to engage with a range of credible multilateral initiatives.

Indeed, the UK government is currently planning to replace its ageing nuclear weapons system Trident with a full gold-plated upgrade, firing on all cylinders. But the government is not getting a particularly easy ride. The majority of the population opposes Trident and its replacement, for pretty obvious reasons: it is a Cold War system that doesn't meet our 21 century security needs and we could spend the vast sums involved - in excess of £100bn ($131.460bn) - on many other useful things, whether in defence or other government budgets.

So the debate about the future of Britain's nuclear weapons is ongoing and will only heat up further in the next three years: 2015 sees a general election where policies on Trident will be in the spotlight; and 2016 sees a parliamentary vote on whether to replace Trident or not. The future of Britain's nuclear weapons system is by no means certain.

Since Britain's coalition government came to power in 2010, it has been internally conflicted over the question of Trident, and the publication this week of the Trident Alternatives Review is a product of that division. In the run up to the 2010 election it was clear that there were differences of opinion, and these hit the headlines during the party leaders' debates . While David Cameron (Conservative) and Gordon Brown (Labour) underlined their commitment to replacing Trident, Nick Clegg drew a clear line by stating that his party, the Liberal Democrats, were opposed to a 'like-for-like' replacement for Trident - four subs with missiles and warheads - and would review what, if any, form of nuclear system Britain needed.

Once in government, the difference between Conservatives and Lib Dems continued. The Conservatives weren't prepared to back down on advocating a full replacement, and the Lib Dems wanted to be able to advocate an alternative. And so the Trident Alternatives Review has been produced by the Ministry of Defence, reporting to the Cabinet Office, to enable the Lib Dems to make that case for an alternative to Trident. All kinds of options have been raked over, during the past couple of years: nuclear-tipped cruise missiles on existing conventional Astute subs, free-fall nuclear bombs to be dropped from planes, land-launches missiles fired from nuclear silos…the list begins to sound like something from a Bond movie. The key problem with the Review was that its remit did not include considering the non-nuclear option – presumably the result of the dominant position of the pro-Trident Conservatives within the coalition government.

As it turns out, the Trident Alternatives Review has rejected all these other nuclear options as insufficient to the task. The only variant on the full-blown four sub option it considered worthy of mention was the possibility of reducing the number of subs from four to three. This is not as simple as it might seem of course. One of the totems of British nuclear policy is so-called "continuous at-sea deterrence" (CASD): a nuclear-armed sub out on patrol 24/7, at unspecified and unpredictable locations, instilling fear into the hearts of our enemies. This requires four submarines, so a reduction to two subs would spell an end to CASD. But there are many who think that is a viable and sensible option, former Labour Defence Secretary Lord Des Browne for one .

Scrapping trident

Whilst a step in the right direction, beginning to break down an antiquated and expensive nuclear doctrine, this is no substitute for the real alternative to Trident: getting rid of nuclear weapons altogether . This was the most important strategic alternative and its exclusion from the Trident Alternatives Review has rendered it pretty shallow and inadequate to the task of addressing Britain's most urgent security challenges.

Any government that tries to avoid and exclude the non-nuclear option will do us all a grave disservice.

Hence CND's publication of The Real Alternative: what the government's Trident Alternatives Review isn't telling you . In short, the question of whether or not to replace the Trident nuclear weapon system is of great security and economic importance. Therefore, ahead of the parliamentary vote in 2016, the full range of options must be explored and the decision must be taken on the basis of what will most contribute to the security of the British people, with a clear understanding of the security challenges of the 21st century.

Non-replacement is a credible option, which offers serious strategic and economic benefits, including: improved national security - through budgetary flexibility in the Ministry of Defence and a more effective response to emerging security challenges in the 21st century; improved global security - through a strengthening of the non-proliferation regime, deterring of nuclear proliferation and de-escalation of international tensions; vast economic savings - of more than £100 billion ($131.460bn) over the lifetime of a successor nuclear weapons system, releasing resources for effective security spending, as well as a range of public spending priorities; and of course adherence to our legal obligations including our responsibilities as a signatory to the nuclear Non-Proliferation Treaty (NPT).

This question of Britain's possession of nuclear weapons is not going to go away. It is in all of our interests, in the UK and beyond, that all options are fully considered when the vote is taken in 2016 and any government that tries to avoid and exclude the non-nuclear option will do us all a grave disservice.

Dr. Kate Hudson is General Secretary of the UK-based Campaign for Nuclear Disarmament (CND). She has held that post since September 2010, having previously been Chair of the organisation since 2003. She is a leading anti-nuclear and anti-war campaigner nationally and internationally. She is also author of 'CND Now More than Ever: The Story of a Peace Movement'.