A report expected to be completed in France this week is awaited anxiously by the Central Bank, Dublin Corporation's traffic department and suppliers of the State's pay-and-display parking meters.

This not-so-old triangle has been going jingle-jangle for the past two weeks over the issue of why meters and the latest generation of £1 coins have proved incompatible. The report by the machine manufacturers, Schlumberger, may provide an explanation.

For the moment the two opposing camps (the corporation and the suppliers are largely in agreement) remain irreconcilable, and the issue has become a metaphor for society at large.

Either the latest generation of coins is just no damned good - the corporation's view, more or less - or the coins are as every bit as good as their predecessors and narrow-minded parking meters are just making unrealistic demands of them - the Central Bank's opinion.

Whatever the truth, the delinquent coins are dropping out of meters and some vending machines in alarming numbers.

The 1999 coin has had an undeniable credibility problem since it first appeared in September.

The bank insists it has the same weight, design and dimensions of all its predecessors and that independent tests - including one by Britain's Royal Mint - have confirmed its copper-nickel composition to be within the allowed 2 per cent plus or minus of the prescribed 75:25 per cent ratio.

Yet while it may look like a duck and walk like a duck, the coin doesn't quite quack like a duck, as a rudimentary experiment confirms.

When dropped it makes a different sound - more of a jangle than a jingle - to its predecessors; a difference which a possible 4 per cent swing in copper or nickel content hardly explains.

The eccentricity took its toll on public confidence early on and the Central Bank had to scotch a number of urban myths which sprang to life.

One was that there was no official £1 issue this year so that all such coins were counterfeit. Another version insisted the new coins were made from beer kegs.

The millennium £1 was dragged into the controversy two weeks ago - groundlessly says the bank because, samples apart, it hadn't even been minted at the time.

The 1999 coins were not minted in Ireland but the bank says they came from a "reliable and respected" European source which had supplied it before. Nevertheless, a spokesman also conceded that further tests were taking place to establish if there was "anything else" in the coin which shouldn't be there.

While such a finding would not surprise the suppliers or Dublin Corporation (there are 700 of the meters throughout the State, but the £1 problem is largely a Dublin one because tariffs are much lower elsewhere),

they accept the end result will probably be the widening of the meters' "acceptance window". The thing to be avoided is "opening the window too wide", a corporation spokesman said.

The spokesman claims he has anecdotal evidence that some vending machines are having the same problem. However, one key indicator, the State's 3,000 Durex machines, suggests otherwise. According to a spokesman, the distributors have not encountered a difficulty "and 80 per cent of our business is £1 coins".

A spokesman for Harringtons Ltd, a Dublin company which has been making and supplying vending machines for 30 years, said its machines' acceptance windows were wide enough to deal with whatever problems the coin has. One in 10 might be rejected but it would usually go through at a second or third attempt.

However, Harringtons predicted "major hassle" when the euro hits the streets in two years. "All the countries are going to be minting their own coins, with different variations. We're going to have to programme our machines with samples of them all."

While the meter dispute is still to be settled, the fact is that the 1999 coin remains legal tender. So what if a legal-minded parker offers the coin to a meter and, upon its rejection, posts a note on his windscreen to the effect that payment has been refused?

"We'll clamp his car," was the corporation's bald response. "We've put stickers about the problem on all the machines and we're replacing them daily as they get pulled off or whatever."

Preliminary findings by Schlumberger, made available to Dublin Corporation last night, are that the problem relates to the thickness of the coins. The 1999 version appears to be thinner than its predecessors.