The State pays more than £1.5 million (€1.9 million) a year in rent to companies run by Mr John Byrne, the property developer who has been linked to the Ansbacher deposits.

Some of the office space was first leased by the State 35 years ago and tenants include the Companies Office and the Office of the Revenue Commissioners.

The Revenue is currently conducting an inquiry into the Ansbacher deposits.

The High Court was told last September that two of Mr Byrne's companies, Carlisle Trust Ltd and Alstead Securities, accounted for £17.5 million sterling (€28 million) of loans totalling £24 million sterling issued by Irish Intercontinental Bank (IIB) from 1991-97 with "back-to-back" security provided by the Cayman Islands bank, Ansbacher Cayman Ltd.

Back-to-back loans, the court was told, allowed depositors to gain access to money in the Ansbacher deposits without bringing the existence of the deposits to the attention of the Revenue. The facility letters for the loans would not mention the cash security provided to back the loans.

According to the Office of Public Works (OPW), the State has leased D'Olier House, D'Olier Street, Dublin, from Dublin City Estates Ltd, a subsidiary of Carlisle Trust, since 1972. The rent is currently £375,000 a year and one of the tenants is the Revenue.

It also pays rent of £450,000 on O'Connell Bridge House, Burgh Quay, Dublin, which it has leased from Carlisle Trust since 1965, and £375,000 a year on 157 to 164 Townsend Street, Dublin, which is owned by Carlisle Trust but leased by the State since 1975.

Alstead Securities leases Parnell House, 14 Parnell Square, Dublin - which houses the Companies Registration Office - to the State. The rent was not revealed by the OPW as it is covered by a confidentiality clause. The rent involved, however, is likely to be in excess of £250,000 a year.

Some of the facility letters for the IIB loans were signed as accepted by the late Mr Des Traynor. Mr Traynor, financial adviser to the former Taoiseach Mr Charles Haughey and the main architect of the Ansbacher deposits, was a director of Mr Byrne's companies from 1961. The companies' auditors were Haughey Boland, of which Mr Traynor was a partner.

Carlisle Trust is the owner of three other Byrne companies - Alstead Securities, Dublin City Estates Ltd and Smithfield Property Development Company Ltd (formerly Endcamp Ltd). Carlisle Trust is understood to be owned, in turn, by Prospect Holdings, an unlimited Cayman Islands company controlled by a Cayman Island trust. It is understood this trust is linked to Ansbacher Cayman.