Today for three hours there will be a debate in Parliament's Westminster Hall on the US-UK Mutual Defence Agreement (MDA). This debate has been jointly sponsored by me and Julian Lewis MP.

This might sound an odd combination as I am passionately opposed to nuclear weapons in any shape or form - and Julian Lewis holds a very
different view of the world, believing in the strategic importance of such weapons.

However, we are debating the Mutual Defence Agreement between Britain and the United States for the first time in more than 20 years.

This agreement was signed in 1958 by the then British and US governments and is supposed to be the subject of a 10-yearly review, with a process put through both parliaments.

In the relative transparency of the US congressional system they debate a message from the President and approve or otherwise his proposal. In the case of Britain, it's all bound up with a miasma of secrecy surrounding anything to do with nuclear weapons and the power over Parliament held by the Prime Minister in his exercise of the royal prerogative relating to treaties.

In 1994 Alan Simpson, former MP for Nottingham South, secured a bizarre late-night discussion on this under the consolidated fund procedure, a quaint and archaic parliamentary process by which MPs could raise any subject they like that related in some way to government expenditure.

No debate was granted in 2004 but after several months of badgering ministers and the Leader of the House over this, the backbench business committee granted this debate.

Separately, a motion has been tabled to the House led by Caroline Lucas, and supported by five other MPs for a formal rejection of the amended MDA.

At the end of the second world war the US discharged two atomic bombs over Hiroshima and Nagasaki. These two weapons killed 300,000 people and maimed many more.

They were the product of the work of the Manhattan project, a huge British and US nuclear research operation conducted with the utmost secrecy throughout the war.

At the end of the war, following Germany's surrender, there was an unseemly rush by the US and the USSR to capture German scientists working for the nazi war machine who could be useful in developing nuclear weapons or rocket systems.

Germany under Hitler was thought to be close to developing nuclear weapons.

The post-war world was full of UN-inspired hope and a general revulsion against war but this did not stop a number of countries developing their own forms of nuclear weapons, often in secrecy from each other, with the US developing a whole new range of weapons.

The USSR exploded its first nuclear bomb in the late 1940s and Britain decided to develop its own independent nuclear weapon.

The British development was so secret that even the Cabinet was denied knowledge of it by PM Clement Attlee and there was no word of it in Parliament.

Indeed, in a bizarre twist, in 1952 Winston Churchill, who was then prime minister again, made a statement in the House of Commons in which he revealed the nuclear test that had just taken place on the Monte Bello Islands off the coast of Australia, and for the first time, publicly announced that Britain had already spent £100 million on this secret weapon, and that Parliament had been denied knowledge of this.

One suspects that his feigned concern about this was actually a sneaking regard for Attlee's ability to maintain such an astonishing level of secrecy for something so dramatic. Secrecy has indeed been the watchword of all things nuclear since then.

The explosion in Australia which prime minister Churchill reported was one of the nuclear tests from which the veterans still suffer.

He went on to explain how they had hoped that nuclear fallout would not affect populated areas. This strange admission ought to be used as the very basis for British participation in the next humanitarian impact of nuclear weapons conference in Vienna next month.

Under the McMahon Act the US was prevented from sharing nuclear information with any other country including Britain or indeed any other member of the Nato alliance.

With unseemly haste the McMahon Act amendments were followed by the MDA of 1958, which led to the sharing of nuclear information and research possibilities and capabilities.

Later, the nuclear Non Proliferation Treaty (NPT) specifically prevented the export of nuclear technology or weapons outside of their own jurisdictions as a way of stifling proliferation. Both the US and Britain claim that the MDA is not in contravention and does not undermine the NPT, a matter hotly contested by many international
lawyers.

The amendments to the existing MDA which are now part of the treaty, approved by the US but not yet by Britain, are to allow collaboration in the purchase of submarine nuclear reactor components and the involvement of US contractors in the British nuclear reactor programme, and also, the sharing of intelligence and information to, allegedly, prevent the spread of nuclear weapons technology.

Existing areas of co-operation include nuclear warheads and modernisation of the current British Trident system, as well as reactor design and exchange of special nuclear materials. It also includes research into the stewardship of warhead stock piles.

Big questions need to be answered by ministers such as, what is the legal compatibility of the MDA with the NPT and the Comprehensive Test Ban Treaty.

Second, what transfers of special nuclear materials have taken place between the US and Britain over the past 10 years and how much this has cost?

Third, I think we're all entitled to know exactly what work is being undertaken at AWE Aldermaston on the development of the new Trident warhead, even though the maingate decision on Trident is not due to be taken for another two years.

There have been conferences on the humanitarian effects of nuclear weapons held so far in Oslo and in Mexico, hosted by their respective governments, and the last one was supported by 135 states.

The attendance showed a serious and decent worldwide concern about the effects of nuclear weapons on life, our environment and, indeed, if ever used, on the world's economic and physical sustainability.

To their shame, the five declared nuclear weapon states, also being the five permanent members of the security council, refused to attend.

The New Zealand government has issued an appeal on behalf of an increased number of participants expected in Vienna, this time from 155 member states, urging all countries to attend.

Despite repeated requests and invitations to do so, the last answer I received from the Foreign Office on this was that they were concerned about the one-sided nature of the conference.

Irony is a great British virtue and the Foreign Office uses it to excess. If it is one-sided to want a nuclear-free world and to seriously examine what happens then a nuclear explosion takes place, then surely they ought to be in Vienna to find out.

The nuclear test veterans who were deceived about the effect of the explosions in 1952 at the very least deserve an answer, as do those people on the Marshall Islands and all over the Pacific who suffer the effects from atmospheric testing.

Jeremy Corbyn is Labour MP for Islington North.