Pacific nation that was site of 67 nuclear tests between 1946 and 1958 accuses states of 'flagrant denial of human justice'

The Marshall Islands is suing the nine countries with nuclear weapons at the international court of justice at The Hague, arguing they have violated their legal obligation to disarm.

In the unprecedented legal action, comprising nine separate cases brought before the ICJ on Thursday, the Republic of the Marshall Islands accuses the nuclear weapons states of a "flagrant denial of human justice". It argues it is justified in taking the action because of the harm it suffered as a result of the nuclear arms race.

The Pacific chain of islands, including Bikini Atoll and Enewetak, was the site of 67 nuclear tests from 1946 to 1958, including the "Bravo shot", a 15-megaton device equivalent to a thousand Hiroshima blasts, detonated in 1954. The Marshallese islanders say they have been suffering serious health and environmental effects ever since.

The island republic is suing the five "established" nuclear weapons states recognised in the 1968 nuclear non-proliferation treaty (NPT) – the US, Russia (which inherited the Soviet arsenal), China, France and the UK – as well as the three countries outside the NPT who have declared nuclear arsenals – India, Pakistan and North Korea, and the one undeclared nuclear weapons state, Israel.

The NPT, which came into force in 1970 is essentially a compact between the non-weapon states, who pledged to not to acquire nuclear weapons, and the weapons states, who in return undertook to disarm under article VI of the treaty.

Although the size of the arsenals are sharply down from the height of the cold war, the Marshall Islands' legal case notes there remain more than 17,000 warheads in existence, 16,000 of them owned by Russia and the US – enough to destroy all life on the planet.

"The long delay in fulfilling the obligations enshrined in article VI of the NPT constitutes a flagrant denial of human justice," the court documents say.

The Marshall Islands case draws attention to the fact that the weapons states are currently in the process of modernising their nuclear weapons, which it portrays as a clear violation of the NPT.

The case against Britain, which has an estimated total inventory of 225 warheads and is in the process of replacing its submarine-launched Trident arsenal, states that: "The UK has not pursued in good faith negotiations to cease the nuclear arms race at an early date through comprehensive nuclear disarmament or other measures, and instead is taking actions to improve its nuclear weapons system and to maintain it for the indefinite future."

The Campaign for Nuclear Disarmament's general secretary, Kate Hudson, said: "The nuclear-armed states continue to peddle the myth that they are committed to multilateral disarmament initiatives, while squandering billions to modernise their nuclear arsenals. The UK government's plans to replace Trident make a mockery of its professed belief in multilateral frameworks – and now in addition to huge public opposition in the UK, it will also face an international legal challenge to expose its hypocrisy."