The number of plastic bags given away by shops in Ireland has fallen by 90 per cent since an environment tax was introduced five months ago.
The move, applauded by green groups, has seen the exchequer's coffers swollen by £2.25m and more than one billion bags saved.
Shoppers in the Irish Republic are now charged about 10p for each bag they take from supermarkets. The success of the project is likely to increase pressure for the introduction of a similar measure in Britain.
The British Government has expressed tentative support for the scheme. The only other country in Europe that has a tax on plastic bags is Denmark.
Last month, a 10-ton whale was found dead on the coast of Normandy after swallowing plastic bags. Conservationists believe the animals mistake the bags for squid.
In the UK, plastic bags can be recycled, but only one in 200 is, despite some schemes introduced by retailers to encourage better use of waste. Shredded and compacted, bags can be used as bedding for roads and home building.
Martin Cullen, the Irish Environment Minister, said the development was evidence that "the mindset is changing and proof that implementation of similar strategies must continue". He said the provision of plastic bags by the 3,000 retailers affected by the new law had been cut by 90 per cent compared with the pre-March total. At this rate, the tax office would collect nearly £6.5m over the year, Mr Cullen said.
Before the legislation was enacted, an estimated 1.2 billion bags were handed out to Irish shoppers without charge each year.
Mr Cullen said: "The reduction has been immediate and the positive visual impact on the environment is plain to see." He said the money raised would be spent on environmental projects and among ideas being considered was the establishment of an office for environmental enforcement.
The minister said: "We are realising that by implementing practical measures such as this, the environment wins."