The nuclear accident at Chernobyl is likely to claim 4,000 lives although it produced less of a danger to public health than many scientists believed, the most comprehensive report on the incident has claimed.

However, scientists have warned that the "sarcophagus" built to contain the damaged reactor has degraded in parts, threatening the structure with collapse which could release radioactive material. A detailed plan to dispose of the tonnes of hig-level radioactive waste around the site of the accident has also yet to be drawn up, though it is nearly 20 years since the accident - the most serious in the history of the nuclear industry - took place.