Tar - the sticky, oily nuisance that has long ruined days at the seaside - is rapidly disappearing from our beaches, as the result of a remarkable, but unsung, environmental success story.
The report, by the authoritative Advisory Committee on Oil Pollution of the Sea (Acops), provides "the first conclusive evidence" that the contamination of Britain's beaches is in "consistent and continuing decline".
It says that incidents of tar pollution, which it has logged for more than 30 years, fell more than fourfold between 1976 and 1996, from 193 incidents to just 44 a year.
New figures, to be published by Acops later this month, will show that they dropped further last year to just 39, the lowest number on record. The fall has occurred right round Britain's coastline, with the exception of the West of Scotland, which is on an important tanker route from the North Sea.
At the same time, there has been a dramatic fall in the number of oil spills from tankers, despite occasional disasters such as the wrecking of the Sea Empress two years ago, which polluted much of the coast of south-west Wales.
Last year, only 16 of the 41,000 tankers that passed through Britain's waters spilled oil - about one-sixth of the 93 incidents reported in the peak year of 1982. Again, this was the lowest number ever recorded.
Dr Trevor Dixon, of the Environment Centre at Buckinghamshire Chiltern University College, who produced the report, said: "For the first time we have conclusive environmental evidence that the maritime transportation industry has successfully responded to political and public pressures for cleaner seas and beaches."
He adds that this is largely due to international laws introduced by the International Maritime Organisation - a little known United Nations agency.
Tankers have become better designed and operated as a result. And deliberate discharges of oil from cleaning tanks at sea - a far greater cause of spills than accidents, and the main source of tar on beaches - are now strictly controlled.
Lord Callaghan, who helped to found Acops and is now its president, calls this a success story. However, the report, Long Term Analysis of Oil Spill Statistics for the Waters around the British Isles, also shows that other types of ships and installations have not followed the oil tankers in cleaning up.
Oil pollution from other types of vessels - mainly discharges of the fuel used to power them - have actually increased. But the oil is much lighter than the heavy tars carried by tankers and, though spills endanger wildlife, it is broken up and dispersed before it reaches the beaches.
Spills from North Sea oil and gas installations far off shore have also shot up, and more than doubled from 1995-96.Reuse content