Northern Bank yesterday issued the first of 50,000 plastic £5 notes, saying they lasted longer and represented a good way to celebrate the millennium. The notes will be the first of their type in the European Union, but Australia has used plastic money since 1988.

Northern which, along with its sister bank National Irish, is owned by National Australia Bank, said the plastic note was easy to launder but difficult to forge.

Notes are waterproof, and allow better anti-counterfeit devices such as see-through features.

They last about four times longer than their paper equivalent.

"It is about the same thickness as a conventional banknote, but when you fold it over then let it go, it will spring back," a spokesman said.

Financial institutions in Ireland and Scotland have been allowed print their own sterling notes since the 18th century. Bank of Ireland was the first to be granted this right from the authorities in London.

Technically, the notes are not legal tender, but represent a promise by the bank to pay the bearer the amount in question.

This arrangement suits the banks, because they must "cover" their own tender with the Bank of England only when the notes actually leave the bank, rather than having to buy notes in advance.