The first exhaustive independent examination of radioactive contamination and leakage from France's nuclear testing grounds in the South Pacific is expected to begin in the next few weeks.
A team of scientists assembled by the UN's International Atomic Energy Agency (IAEA) will spend at least a month on the Mururoa and Fangataufa atolls, taking samples of sea, soil, land plants, fish, and sea-floor sediments.
France first requested the study by the agency last year, in the belief that it would demonstrate that more than 10 years of underground nuclear tests on the atolls had not caused severe contamination. The atomic tests ended last week; they may be the last France carries out.
The draft terms of reference for the study, seen by the Independent and welcomed by the environmental group Greenpeace, are about to be sent from the IAEA's Vienna headquarters to Paris. Provided the French government approves, the first scouting expedition will take place next month. The terms say the study will be ''objective, comprehensive and independent'', and will take into account the data gathered by the French over decades of testing.
''If this is to be a meaningful investigation, then the French have to give the agency ... full access to all of their logs,'' said Patricia Lewis, director of Vertic, a London-based think-tank which studies whether nations keep their treaty obligations. ''In the past they've never been open enough - this is a chance to make amends.''
David Kyd, spokesman for the IAEA, said: ''There's no question of us just taking the French data and giving it a quick look-see. We're going to gather our own information and compare our results with the French ones.''
The agency has budgeted up to $1.5m (pounds 1m) for the inquiry. It expects to make its findings public in 18 months.