The nuclear weapons age began on 16 July 1945 when the United States exploded the first nuclear bomb, codenamed 'Trinity' at Alamogordo, New Mexico. The Soviet Union was next to explode a bomb, in August 1949. Other countries followed: Britain's first test was in October 1952; France's in February 1960; China's in October 1964 and India's in 1974.

Since 1945, there have been 2,046 tests worldwide, about one nuclear test every nine days for the last fifty-one years. The U.S. has carried out 1,030 nuclear weapon tests; the former Soviet Union has done 715; France, 210; Britain, 45 and China also 45. India has exploded one nuclear device, which it claimed was for peaceful purposes.

Nuclear weapon test explosions have been carried out in the atmosphere, underground, and underwater. They have occurred on top of towers, onboard barges, suspended from balloons, on the earth's surface, deep underwater, deep underground and in horizontal tunnels bored into the sides of mountains. Nuclear bombs also have been dropped by aircraft and fired by rockets up to 200 miles into the atmosphere.

Wherever nuclear weapons testing has occurred there have been environmental problems. Large areas of land are contaminated as a result of atmospheric tests and the long-term consequences of underground nuclear testing are unknown. Fallout from the peak years of atmospheric nuclear testing in the 1950s and 1960s, contaminated food, milk and water around the globe.

In 1954, India made the first proposal calling for an agreement to ban nuclear weapons tests. In 1958, the U.S., Soviet Union, and the U.K. began a Conference on the Discontinuance of Nuclear Tests in Geneva and the U.S. and the Soviet Union also agreed to a nuclear test moratorium. Agreement was all but reached on banning all atmospheric and underwater tests, tests in space, and underground testing above a set explosive power with a moratorium on explosions below that level. The unresolved issues were expected to be settled at a summit in May 1960. But the scandal following the shooting down by the Soviet Union of a U.S. U-2 spy plane over Russia, lead to the cancellation of the summit. During 1961, both the U.S. and the Soviet Union started testing again.

Some progress was made towards limiting nuclear testing during the remainder of the Cold War. However, despite an end to nuclear testing in the atmosphere and temporary halts to nuclear testing for some periods of months by one or more of the nuclear powers, the nuclear arms race ground inexorably onwards and nuclear testing continued.

But nuclear testing was never without controversy. Greenpeace was founded in 1971, in response to nuclear weapons testing by the U.S. at Amchitka in the Aleutian Islands of the coast of Alaska in 1971 and, in the following year, conducted its first protest against French testing at Moruroa in the South Pacific.

Finally, in 1991, hopes for an end to nuclear testing started to rise again. The U.S., U.K., Soviet Union and France agreed to self-imposed moratoria in their nuclear testing programmes (only China refused to join) and in November 1993, the Conference on Disarmament in Geneva finally received a strong mandate to negotiate a legally-binding Comprehensive Nuclear Test Ban Treaty. Work formally began on a CTBT in Geneva in early 1994.

During 1994, talks got bogged down on details and several fundamental issues. France and the U.K. wanted to continue carrying out 'safety tests', China wanted to be allowed to carry out 'Peaceful Nuclear Explosions', and the U.S., Russia, the U.K., and France all wanted to be allowed to do small nuclear explosions.

In 1995, nuclear tests by China and the announcement of a resumption of testing by France, lead to increased pressure on the negotiations. In August, France, the U.S., and the U.K. committed themselves to a so-called '0-yield' CTBT which would ban all types of nuclear tests for any purpose, irrespective of how small the explosion. Nonetheless, by the end of 1995, there were still many disagreements - and France and China continued to plan further tests. France ended its test programme in January 1996 and announced the closure of its test site in the Pacific. China announced a moratorium on its testing at the end of July after its 45th, and perhaps the world's last ever, nuclear test explosion.

Today - the anniversary of the atomic bombing of Nagasaki - the outcome of the talks hangs in balance and the final result is deeply uncertain. Perhaps in the next few days, after more than 51 years of nuclear tests and forty years of effort, the goal of a treaty prohibiting all nuclear tests, forever, anywhere may finally be attained. Or, as has happened before, the opportunity could slip away once again. The draft text is far from perfect, but it would be adequate to end all testing.