The principality's powerful audit committee is to investigate why these costs have seemingly spiralled. The committee will now scrutinise paperwork going back seven years for any signs of incompetence, sleaze or irregularities.
Yesterday, Rod Richards, the Welsh Conservative leader, called for a full inquiry: "This matter must be fully investigated. It is a matter of great concern that so much money is being spent."
The former Welsh secretary, Ron Davies, opted to establish the Assembly at Cardiff Bay rather than spend an estimated pounds 40m renovating the White House-style City Hall building in Cardiff. The cost of housing the Assembly in three buildings on the Cardiff Bay site - a five-storey office called Crickhowell House, the neo-gothic Pierhead Building and a new debating chamber - was originally estimated at pounds 17m, a figure which officially rose to pounds 20m this month.
But, according to the leaked documents, hidden costs from the Cardiff Bay site will push the bill up to at least pounds 80m over the next 25 years, and at the end of that period, the main building will still not be owned by the Assembly.
The major beneficiary from the decision to site the Assembley in Cardiff Bay is Associated British Ports, which owns the site for the new debating chamber and Crickhowell House, now called the Assembly building. ABP receives about pounds 2.3m in rent each year as part of a renewed lease which has been extended to 25 years.
The costs of the waterfront home make a nonsense of the much-hyped deal under which Mr Davies paid just pounds 1 for the Assembly site which was also owned by ABP. Mr Davies could not be contacted for a comment yesterday.
A spokeswoman for Alun Michael, the First Secretary, said: "There is nothing to hide, it is all documented on the internet. Capital costs are well within the projected pounds 20m figure. What you are talking about is the running costs. The politicians never asked what the running costs were."Reuse content