The key questions about the Sports Campus Ireland project are straightforward: Does it make any sense? And what is it likely to cost at the end of the day? The answer to the first question is No and the answer to the second is "nobody knows" - not even those who are planning it.

The Abbotstown adventure - incorporating Stadium Ireland, otherwise known as the Bertie Bowl - is the biggest infrastructural investment in the history of the State. From an initial estimate of £281 million in January of last year, it has grown to £550 million and would probably cost £1 billion or more - if it is actually built.

The current £550 million estimate does not even include the bill for relocating the State laboratories currently accommodated on the 500-acre site in west Dublin. This is now estimated at £193 million - more than double what the Government was told it would be last February after it had decided to proceed with the project.

The latest set of figures make only minimal allowance for construction cost inflation, which could be very high. Last year, the Department of Health experienced a 22 per cent increase in construction costs for hospitals and other health facilities. If that trend was to continue for five years, costs would soar by more than 100 per cent.

And it would be 2005 at the earliest before Stadium Ireland was completed, if it gets off the ground at all. Figures for 15 stadiums built in the US in recent years show an average cost overrun of 90.6 per cent - though this is stated to be 73.4 per cent in the feasibility study for Abbotstown.

The study, compiled by PriceWaterhouseCoopers (PWC) and published in January of last year, had something of a cheerleader quality. It talked about the vision of a national stadium "of which Irish people can be proud" that would "compete with any stadium worldwide for international events" as well as being "an icon design for Ireland".

But Abbotstown wasn't just to get a stand-alone stadium with seating for 80,000 spectators. Using language that would not have been unfamiliar to Nicolae Ceaucescu, the consultants recommended that the site should be developed as a "Campus of Sporting Excellence", to include a 15,000-seat indoor arena and numerous other facilities.

All of this was to be installed on a site adjoining the M50, repudiating established Government policy - as spelled out in the 1994 Dublin Transportation Initiative final report - that the spread of commercial, industrial and leisure-related development should be strictly curtailed along this corridor to protect the M50's intended role as a bypass.

Astonishingly, the feasibility study assumed that 45 per cent of the 80,000 spectators attending a major event in the national stadium would travel to and from Abbotstown by car, raising the spectre of traffic congestion on a gargantuan scale; indeed, the 14,400 parking spaces to be provided were factored in as part of the stadium's revenue stream.

The issue of cost was fudged by the PWC-led study. Of the overall estimate of £281 million, it was assumed that the arena as well as an indoor tennis facility, sports science and medical centre and a variety of "multi-purpose halls" could be provided for just £51 million. It has since emerged that the arena alone will cost more than twice as much.

Over the past year or so, the rather vague initial list has been expanded to include a velodrome, a golf academy and an aquatic centre, which will have an Olympic-size swimming pool. The latter, incidentally, is the only element of the Sports Campus project for which a contract has been signed; it is costed at £41 million.

Campus and Stadium Ireland Ltd, which was set up to "drive" the project, fast-tracked the aquatic centre so that it could be ready in time for the Special Olympics in June 2003. Still operating without any legislative mandate, CSID decided on a DBFOM (design, build, finance, operate and maintain) contract to procure it from the private sector. It was when this shadow State company opted to extend DBFOM to all the other facilities proposed for Abbotstown, including Stadium Ireland, that it ran into trouble - particularly over its insistence on going ahead with the selection of panels of architects against the advice of the Office of Public Works, as project manager for the scheme.

Though intended to ensure "architectural excellence", the competition succeeded in alienating a sizeable number of Irish architects and turned out, in any case, to be meaningless as the six international consortiums interested in bidding for Sports Campus Ireland could not be compelled to choose any of the architects from CSID's approved lists.

The OPW made sure this was explicitly stated in the outline bid documentation, which was eventually sent out to the six consortiums on April 6th. A month earlier, somewhat ominously, it resigned as project manager to become adviser to the Department of Tourism, Sport and Recreation, where responsibility for Abbotstown now resides.

WHAT CSID needed to nail down was the issue of "bums on seats" - in other words, how many major events per year were likely to be held in Stadium Ireland. The bidders also needed to know this, otherwise they would have found it difficult - if not impossible - to make credible tenders; hence the urgency of getting the FAI and GAA on board.

And so, arms were twisted and funding offered to secure their participation in the project, at an estimated cost to the Exchequer of £120 million or more. The GAA needs the £60 million it has been offered to complete Croke Park, even if the deal entails playing some of its matches at another 80,000-seat stadium somewhere else in Dublin.

Given CSID's commitment to "architectural excellence", the stadium alone is likely to cost £320 million, at a ballpark figure of £4,000 per seat - again, without allowing for construction cost inflation. The only commercially viable element of the entire Abbotstown project would be the indoor arena because of the multiplicity of events it could stage.

Stadium Australia, which was held out as a model for its putative Irish equivalent, is in deep trouble not much more than six months after staging the Olympic Games. Its athletics track has already been ripped up and the stadium itself is being made more "intimate" by pushing the stands closer together. If this doesn't work, bankruptcy looms.

The Homebush Bay sports campus, with the stadium as its centrepiece, is located at the edge of Sydney, a city with a population of 3.5 million. If an 80,000seat stadium and all of the ancillary facilities are not viable there, how can Dublin, with a third of Sydney's population, hope to sustain two 80,000-seat stadiums? It just doesn't make sense.

And yet grown men and women, from the Taoiseach down, remain doggedly committed to this project. Files released under the Freedom of Information Act are full of frenetic activity, but also of foreboding about the spiralling costs of the Abbotstown adventure and the potential exposure of the Exchequer to a colossal, uncountable bill.

It is clear from the chronology of events published below that the project has been railroaded through the system, much like London's ill-fated Millennium Dome. At key points, vital information was not made available before crucial decisions were taken and, on occasion, Cabinet procedures were breached in the interest of progressing it.

The Progressive Democrats appear to have woken up to what is going on and are now calling for the project to be "scaled down". With capital expenditure already being cut back across the board, Abbotstown must surely be a candidate; last week's announcement that its cost is to be subjected to an "external overview" is clearly a straw in the wind.

Only when the bids are opened on May 31st will we get a real idea of the price tag for Sports Campus Ireland and whether, in Bertie Ahern's phrase, it resides "in cloudcuckoo-land or not". If it still proceeds then, will it be simply because, as Dr Jim McDaid once put it, "every other banana republic in the world has their own national stadium"?