In her interesting description of the refurbishment of Kahn's Yale University Art Gallery (AJ 30.11.06) Sarah Jackson makes the comment, almost by-the-by, that 'primacy is given to the idea, over the actual fabric' in the conservation of 20th-century buildings.
Whether this should be the case is the key issue for those involved in the repair of buildings from the past 100 years.
At last week's Mending Modernism conference, English Heritage's Diane Green spoke up for the importance of the 'real thing' - a lone voice that needs to be strongly endorsed.
The previously much-praised 'restoration' of Owen Williams' Boots D10 building - (Grade I listed but fitted with a new curtain wall to meet the Health and Safety standards required to allow toothpaste to continue to be put in tubes inside it), must be the prime cautionary example - it won a Europa Nostra Conservation Award in 1996, but with only 10 years hindsight it is already clear that much of the point of this pioneering Modern Movement building has been lost.
Twentieth-century buildings are incredibly varied in their approach to materials and craftsmanship, as well as design ethos and principles. Each needs a clearly thought-out strategy - which may need to include looking for an imaginative new use.
But to think of the conservation of 20th-century buildings as a separate practice - with its own rules and assumptions completely divorced from the conservation of earlier buildings - is crazy. If we are not careful we will soon be surrounded by expensive replicas - surely not the point.
Catherine Croft, director, the Twentieth Century Society