Architecture: Mickey Mouse won't like it one bit: A new 'interpretation centre' brings the late 20th century to the gate of an ancient castle

ST JOHN'S Castle, Limerick, writes Jonathan Glancey, was built by the Normans, knocked about a bit by Cromwell's men, and attacked by cannons and mortar bombs during various wars against the English.

The dust appeared to have settled over these ancient walls - until the steely new visitors' centre designed by Sean O'Laoire, of the Dublin practice Murray O'Laoire, raised the hackles of conservationists who believe that it treats the 700 year-old castle in cavalier fashion. This gutsy new building, wholly ahistoric in style, has opened at a time when Ireland is in the grip of a noisy debate over the nature of visitors' and interpretation centres at historic sites.

'Like an increasing number of people in Ireland, I don't want to see a Disneyland approach to ancient monuments,' says O'Laoire. 'Half-way through the project we convinced our client that we should be able design a building of today, a kind of time machine that takes you into the heart of recent archaeological discoveries made at the castle, without any pretence that the new structure is part of the old'.

O'Laoire has, however, enjoyed making design references to castles. The centre is reached over a white-painted steel 'drawbridge'; once inside, the visitor descends on delicate steel ramps suspended from the skeletal structure of the building to view archaeological finds including military and religious artefacts, some dating from before the construction of the castle itself. The undercroft varies in depth from 13ft to 23ft, the ramps rising and falling to allow visitors to get as near as possible to various discoveries that have been left where they were found.

Above, the new architecture provides an appropriate home for the electronic wizardry deemed essential for up-to-the-minute visitors' centres, including an audio- visual display and other forms of interpretative information (plus, of course, the inevitable shop). The upper floors also house display galleries.

The new centre - as rigorous in its structure and simplicity as the Norman castle was when it was built in the 12th century - has been designed so that its structure at no point touches the old walls. Although intended as a permanent addition to the castle ('or as permanent as a steel structure will allow,' says O'Laoire philosophically), the centre could be removed, lock, stock and neoprene gasket, at some point in the future and the castle returned to its pre-Interpretation Era state.

But who would want to remove such a sensible addition? In his own late-20th-century way, O'Laoire has captured the spirit of castle architecture. His palette of materials might seem new, yet his approach is one that the bold Normans would have approved of. 'And we've all forgiven the Normans by now,' says O'Laoire, hoping, perhaps, to be forgiven by those who still want their history wrapped in fake period style.

(Photograph omitted)