Come to Courtown, they said, and see for yourself how the place has been destroyed by the tax incentive scheme for traditional seaside resorts. But nobody could quite convey how bad it really is - and on a scale so vast that it is almost beyond belief, even in Ireland.

Courtown in Co Wexford, never much to write home about, is being turned into a visual and environmental slum. The devastation is more widespread than anywhere else and is as bad, in its own way, as the manic over-development that discredited the Costa del Sol.

From Courtown Golf Club southwards to Poulshone - a distance of less than 10km - it seems as if every available field along the narrow, bumpy coast road has been colonised for purpose-built schemes of holiday homes, some as large as suburban housing estates.

More than 1,000 new houses have been shovelled into this coastal strip over the past two years, and there are yet more either under construction or in planning. Building activity has also spread to Ballymoney and other areas outside the main tax incentive zone.

The new estates have names like Ardamine Grove, Glenbeg Point, Harbour Court and Seamount Village. Huge billboards feature maritime logos, usually a yacht in full sail or a scallop shell, or paint a picture of blue water and sun-drenched white beaches from the tropics.

Way down the narrow, rutted side road to Roney Point, Warren Estates of Gorey has a big yellow billboard heralding what it describes as a "stunning development of only 26 detached 3 and 4-bedroom bungalows on an elevated 16-acre coastal site". It is to be called Roney Bay.

Beyond it, where the road begins to fizzle out and you would never expect to find another development site, a field recently full of buttercups has just been churned up by the bulldozers to make way for yet another scheme, with hardcore piled up for its foundations.

The largest of the new housing estates around Courtown contain up to 150 units. Riverchapel View, for example, is an enormous, tightly-packed scheme of miniaturised houses which seems to go on forever. If you look through any gap, all you can see are yet more houses.

Hooke and MacDonald, who once specialised in selling apartments in the centre of Dublin, are the agents. Other Dublin-based firms involved in handling holiday homes in the area include Sherry FitzGerald, Hamilton Osborne King and Phillips Partnership.

Ganly Walters, another Dublin agency, is selling "superior homes of character" in a scheme called The Village, Ballymoney, with mortgages available from Bank of Ireland. Prices for these dormer bungalows start at £130,000, even though it is outside the tax incentive zone.

According to one local estate agent, who did not wish to be identified, houses in the seaside resort designated area are being sold exclusively to investors - "mainly Dublin-based business people who maybe got a big income tax bill and need to find a tax shelter for their money".

The main attractions of the scheme are that the price of a holiday home (less the site cost) can be offset against "all" income, not just rental income, over 10 years, and that up to 50 per cent can be written off in the first year - ideal for anyone facing a hefty bill from the Revenue.

In theory, every qualifying house must be rented out as a holiday home for 10 years. However, there are stories of unscrupulous transactions involving two friends purchasing equivalent houses and ostensibly renting them out to each other, purely to avail of the tax scheme.

Even Courtown Woods have fallen victim to it. This extensive semi-natural woodland behind the sand dunes along the north beach is a unique landscape feature for any holiday resort, but it has already been compromised by a partial clearance for an estate called Forest Park.

Marketed by Hooke and MacDonald with the aid of another huge billboard featuring a yacht in full sail, it has more neo-traditional cottages with high roofs to accommodate first-floor bedrooms, as well as larger detached houses with generous semi-circular bay windows.

The scheme was developed by a local consortium and is reported to have raised £1.5 million towards the creation of a Waterworld-style adventure playground in a nearby section of the woods. The rest of the woodland, some 200 acres in total, is being "restored" and opened up.

Apart from a lick of paint in a few cases, Courtown's hotels look much the same as ever. Though they, too, could have availed of the tax incentives to upgrade and extend, they do not seem to have done so.

As in the 14 other designated seaside resorts, practically all of the investment under the scheme has gone into holiday homes. Courtown's advantage is that it is within easy driving distance from Dublin thanks to improvements to the N11 - notably the Arklow bypass.

Generally, holiday homes are terraced or detached, with small gaps in between and latticed timber screens to provide a degree of privacy for their occupants. In design terms, they range from reworking the traditional cottage or gate lodge to fairly standard suburban models.

Some of the houses are gable-fronted with decorative bargeboards (moulded rather than carved) and a few even have finials. Others have slate-hooded porches or small conservatories, while nearly all have steeply pitched roofs to accommodate a first-floor dormer level.

Every estate comes complete with white concrete footpaths, black tarmac driveways and street lighting; some of them, such as Sandy Cove in Ballymoney ("discerning holiday homes", the billboard says), even have Versailles-style entrance piers in reconstituted stone.

Hedgerows are usually cleared away to be replaced by dwarf stone walls, wicker fences and footpaths. Landscaping is suburban in style, though some developers have at least planted native species and others have attempted to reconstitute hedgerows on their road frontage.

The overall impact on the landscape is devastating, however. In an area which had experienced only the haphazard, almost organic, development of individual holiday homes and often-ugly caravan parks, a relentless process of suburbanisation is well under way.

Gone are the days when people were quite happy to spend a couple of weeks in timber holiday homes with corrugated roofs. Now, they demand "all mod cons" in houses strikingly similar to the suburban homes in Dublin or elsewhere where most of them generally live.

Since there is no sewerage in Ballymoney and it will be at least three years before a proper treatment plant is provided in Courtown, new estates are operating on biocycle systems - in effect, larger, more sophisticated septic tanks - though there are doubts that these will work if used intermittently.

Many of the more expensive houses have a main bathroom, an en suite one and a guest loo. During the peak holiday season, a lot of extra toilets are going to be flushed, putting a huge additional demand on supplies of piped water in an area which already suffers summer shortages.

Some developers have bored their own wells to be sure of getting a supply. Several of the new housing estates have large green cylindrical tanks to store water for use by residents. But even these measures are unlikely to be sufficient to guarantee a constant supply of water.

And where will all the sewage effluent go? Ms Karin Dubsky, of Coastwatch Europe, who has a home in Ballymoney, points to evidence that the summer influx of holidaymakers into the area pollutes local watercourses and even beaches. "It can only get worse," she says.

With at least 1,200 houses already built and yet more still under construction in Courtown's coastal strip, there are also concerns about the traffic impact: every house will have at least one car and the network of narrow roads is already clogged by summertime jams.

Last April An Bord Pleanala - which has taken a creditably critical view of tax-driven schemes of holiday homes - refused planning permission to Mr David Cullen, a Dublin-based developer, for 69 houses, three commercial units and a clubhouse at Ballymoney Lower.

Having taken into account the scale of this scheme, the absence of public water and sewerage facilities to service it and the deficient road network, the board said it would be "prejudicial to public health and would be unacceptable in terms of traffic safety."

This ruling overturned a decision by Wexford County Council to grant permission. The council seems to have taken the view that its job was to facilitate development, especially in an area designated by central government under the seaside resorts scheme.

The scheme's unique appeal is that there are so many beneficiaries, not least farmers in the Macamores - a difficult area to work because of its marly soil - who have seen the value of their land jump from £3,000 to £5,000 an acre to a staggering £80,000 to £100,000 an acre.

Others include the developers who bought up the land and turned it into estates of holiday homes, the designers and estate agents who have earned commissions on every scheme, the builders who built them and, of course, the investors desperately seeking lucrative tax shelters.

Waiting in the wings with their cash tills are the local publicans, restaurateurs and shopkeepers. But even they must wonder whether the availability of so many holiday homes will in itself deliver hordes of additional free-spending visitors, particularly out of season.

It seems unlikely that the holiday homes will achieve high occupancy levels from October to May, other than on bank holiday weekends.

In the first week of this month, traditionally the start of our summer, there were cars - mostly English-registered - parked outside just a few.

Mr Niall Cussen, president of the Irish Planning Institute, says the seaside resorts tax incentive scheme is just the latest in a long line of government-sponsored initiatives which lack any spatial dimension. And what it will leave, he fears, is a plethora of ghost housing estates.

The jury is out on whether the concept is viable at all. "It's crystal ball stuff as to how it's going to go," one local property expert admitted. But there is already one very definite loser - the landscape - and there will be more as water, sewage and traffic problems intensify.

How the remaining farmers, some with fine houses and outbuildings, will be able to survive in a suburbanised environment is anybody's guess. Perhaps, in the end, they too will take the shilling and yield up their marly soil to be covered by classically unsustainable development.

There is one final, ironic postscript. In September, Wexford County Council will publish a draft plan for Courtown. Just a few months later, on December 31st, the seaside resorts scheme is due to expire, having done its damage. Development has preceded the plan. It is too late.

Courtown is one of the areas featured in Coastwatch Europe's 1999 international conference, which is on today at Dublin Castle. The theme this year is "Planning, Protection and Sustainable Use of Coastal Resources". Further details from Ms Karin Dubsky, telephone 055-25843.