Imagine being the owner of, say, a 60-acre farm in Co Dublin, which the local authority in its wisdom has just rezoned for suburban housing. Suddenly, and without having to lift a finger, you could be a millionaire several times over. It's better than a Lotto jackpot.

That's what is happening throughout the Greater Dublin area, and it's no surprise to learn there has been a frenzy among landowners to have their green fields turned into gold. And with residential land now fetching up to £1 million an acre in the most sought-after areas, who could blame them?

Even the British government is cashing in. Glencairn, its longtime embassy residence on 34 acres in south Co Dublin, is now up for sale, and there has been speculation that it could make as much as £30 million, a very good return on a country house bought for £35,000 in 1956.

Whoever buys it will probably have to preserve its fine stand of mature trees, as well as the house itself. But otherwise, Glencairn is likely to be covered in yet more "luxury" commuter belt homes, just like the sprawl of suburban housing which has crept up to its gates like Birnam Forest come to Dunsinane.

The Phoenix Park racecourse, home turf of successive British viceroys, also seems destined to be developed for housing as well as a hotel, some retail and high-tech offices. The former owners may regret the loss of their controversial casino scheme, but they have recently bagged £37 million on the 100-acre site. And John Byrne, the veteran property developer, is likely to make a huge killing from Fingal County Council's decision to rezone two large chunks of the greenbelt between Baldoyle and Portmarnock for housing. He has been sitting on this property, which includes another former racecourse, for over 20 years.

There are also strong indications that numerous parcels of agricultural land in the Dublin commuter belt have been acquired by speculators in the confident expectation of rezoning. In many cases, this involves speculators buying "options" from landowners and then splitting the proceeds when they get the right result.

The Fingal draft development plan hasn't yet been placed on public exhibition for the statutory three-month period. Such is the "hysteria" among landowners to have their land zoned, as one Labour councillor put it, that it is bound to generate an avalanche of rezoning submissions when it finally goes on display.

Thousands of acres have already been rezoned in the latest spree and thousands more may go the same way by the time councillors finish their deliberations. Yet all of this is being done in a vacuum, in advance of the completion of a study to formulate strategic planning guidelines for Greater Dublin.

Dun Laoghaire-Rathdown was first into the breach with its draft county plan. This was exhibited for three months in the summer of 1997, submissions were then considered by councillors and the changes they made were publicly displayed for a further month last spring. The final plan was formally adopted on July 13th.

Altogether, it rezoned 234 acres to residential, lifted a "low density" restriction from a further 293 acres (mainly in Cherrywood) and zoned 126 acres for industrial or commercial development. Mostly proposed by the county planners, this is quite modest compared to what is going on in Fingal and South Dublin.

One of the most damaging changes made by the councillors was at Carrickmines, where the Fianna Fail group spearheaded a 31-acre industrial rezoning. Since a large part of this site is required for a motorway interchange, the council will have to pay 10 times as much to buy the land it needs as a direct result.

Another change made against all planning advice involved the rezoning of a 21-acre field for low-density housing right in the middle of the greenbelt separating Shankill from Bray. The sponsor of this proposal, Cllr Larry Butler (FF), is now chairman of the council's strategic planning committee.

Wicklow County Council has rezoned a swathe of the greenbelt just north of Bray as residential, even though it is across the border in Dun Laoghaire-Rathdown.

The council has also been reprimanded by the Minister for the Environment, Mr Dempsey, for proposing to rezone more than 70 acres of land near Greystones at a density of just one house per acre. With the DART being extended to Greystones, the Minister takes the view that the housing density should be much higher.

Wicklow county councillors took grave exception to Mr Dempsey's "interference", but it is believed he has since received a formal letter indicating his submission will be taken into account in considering the draft plan. However, if they do not increase the densities, he could use his power to amend it.

Fingal County Council has no qualms about housing density. Its draft county plan, soon to go on public exhibition for three months, would rezone extensive tracts of land in Balbriggan, Portmarnock, Baldoyle and Blanchardstown for higher-density housing while creating a vast new "mixed-use zone" around Dublin Airport.

Residents' associations in Lucan have decided to fight back. They formed a coalition called ALARM (All Lucan Against Rezoning Madness) to campaign against the rezoning of 530 acres south of the already sprawling built-up area for more housing. But it has since been approved by South Dublin County Council.

This particular rezoning was included in its draft development plan on the initiative of the county manager, Mr Frank Kavanagh, against the advice of the chief planning officer, Mr Enda Conway. Despite lodging more than 3,000 objections, ALARM did not manage to persuade the county councillors to overturn it.

South Dublin's draft plan, published last December, also rezones a strip of 200 acres along the southern rim of Tallaght, running up to the foothills of the Dublin Mountains, as well as extensive tracts around the historic villages of Newcastle, Rathcoole and Saggart. And all of this came before the councillors got their hands on it.

When they did, a further 190 acres in the Liffey Valley fell to housing, including 144 acres at St Edmundsbury, which are the subject of a current planning application. Local residents' associations are now mobilising to oppose these changes, which are included in a second public display of the plan, ending on November 9th.

Coincidentally, the initial three-month exhibition of Kildare County Council's draft plan ends on November 10th. It does not rezone any further land, but allocates population parameters for each town and leaves the details to be worked out later in local development plans for towns such as Maynooth, Celbridge and Kilcock.

Naas UDC, which is legally independent of the county council, jumped the gun last week by voting to adopt a population target of 22,000, boosting the present figure by 50 per cent. However, more sober voices suggest that major rezonings in Fingal and South Dublin should relieve the pressure on Kildare, Meath and Wicklow.

Kildare County Council lodged a strong objection to South Dublin's decision to lift the "cap", imposed in 1993, setting a limit of 250,000 square feet on the size of the Liffey Valley shopping centre, which opened this week at Quarryvale, "where the M50 crosses the N4" as its slogan proudly proclaims.

What worried Kildare was that the strategically located Quarryvale centre, the archetype of an out-of-town retailing machine, would have a negative impact on retailing in towns such as Leixlip and Maynooth. But its concerns will hardly worry South Dublin, as it shamelessly chases a new rates base.

That was always the great danger inherent in the 1994 sundering of Co Dublin into three quite separate "counties", co-ordinated by a virtually powerless regional authority; whatever about "having regard to the metropolitan interest", none of them was going to shun an opportunity to rake in commercial rates revenue.

Meanwhile, the strategic planning guidelines that would surely influence schemes such as Quarryvale will not see the light of day until next January. Though it was plainly clear that such guidelines would be required at least since 1994, it was not until last February that consultants were appointed to draft them.

Brady Shipman Martin's study takes on board other issues, such as housing density, sustainable development and the relationship between land use and transportation. As for the current development plans by the seven local authorities in the Dublin and mideast "regions", they are being treated as "inputs" to the study.

The consultants, who are reporting to a steering committee chaired by the city manager, Mr John Fitzgerald, have invited the public to spell out its views on how Dublin should develop. Questionnaires are available at all public libraries throughout the area, with October 30th as the closing date for responding.

By the time the guidelines are adopted, however, every one of the region's local authorities - Dublin Corporation and Fingal, South Dublin, Dun Laoghaire-Rathdown, Meath, Kildare and Wicklow County Councils - will have adopted their development plans, mapping out the paths they intend to take for the next five years.

These plans, rather than the belated strategic planning guidelines, will determine the future of Greater Dublin, given that they coincide with an expected peak period in household formation.

The main beneficiaries are the landowners, whose huge windfall gains will be apportioned across every building site passed on to house-buyers.