For a man who wrote the British Standard Guide to the Principles of the Conservation of Historic Buildings (BS 7913), James Simpson of Edinburgh practice Simpson and Brown is remarkably non-doctrinaire.
'I'm an active member of the Society for the Protection of Ancient Buildings but I see myself as a liberal not a fundamentalist, ' he says.
If proof were required of his liberal stance, it is his work on projects with former employee Richard Murphy. Simpson & Brown does the careful repair of the old fabric which then enables Murphy's interventions. 'If I have any argument with Richard it is that he denies that anything to do with an old building is architecture with a capital 'A'. He tends to see the old building as a ruin he can inhabit - but I can live with that, ' says Simpson.
The son of an architect who ran 'a small, decent, country practice', Simpson has spent more than 30 years specializing in historic buildings, including work with Sir Bernard Feilden - 'both professionally and personally, a loved and respected mentor.'
His own practice, established with Stuart Brown in 1977, now has five partners and 30 staff working from a converted manse in the docklands at Leith.
Initial training in Ian Lindsay's office in Edinburgh in the late '60s, followed by study in the school of architecture at Edinburgh College of Art, led to an abiding love of the architecture of the 18th century and particularly William Adam, the father of the Adam brothers.
'To work with historic buildings you need to be a bit scholarly, ' he says - a comment that suits the man who ensured the publication of a reduced facsimile reprint of Adam's Vitruvius Scoticus in 1980.
He has also been central to initiatives such as the Scottish Lime Centre, the Scottish Historic Buildings Trust, and the Scottish Redundant Churches Trust.
Although intimately connected with conservation he dislikes being typecast as a conservation architect. 'Conservation remains architecture, and good architecture requires good architects. So often it's not what you do but how you do it - it is the subtlety and judgement which you bring to the work that makes all the difference.'
This seems increasingly true when questions of sustainability arise. 'There's a lot of talk about conservation and sustainability being contradictory, ' says Simpson. 'They are not contradictory, they are interlinked absolutely. It was a little difficult in the '70s to realize just why one was conserving buildings. One seemed to be conserving them as an indulgence, a sort of elitist activity - and I think that is what the architectural profession didn't like about conservation.'
So it may come as a surprise that he describes Simpson & Brown's recent awardwinning Scottish Seabird Centre at North Berwick (AJ 2.11.00) as the practice's best building - 'and it was nothing to do with me.
There is no antithesis between creation and conservation, they are complementary.
Having come to this view, I have a newfound wish to create as well as to conserve.'
For many years Simpson taught parttime on the course in architectural conservation at Edinburgh College of Art.
Yet, liberal or not, he remains critical of some recent developments in conservation theory. 'I've never been a believer in this dreadful mantra 'conserve as found' which is thrown at us again and again. I've also become deeply worried about the Burra Charter and the Conservation Plan. There seems to be a view that there is only one way of doing things. Look at the terrific contrast of approach today between say, the Great Hall of Stirling Castle (AJ 8.6.00) and what the National Trust for Scotland is currently doing at Newhailes. You take each building on its own merits.'
One of the most important houses of the Scottish Enlightenment, Newhailes is being conserved largely as a time capsule. It takes English Heritage's approach at Brodsworth one step further by using minimal intervention both inside and out. 'I'd have loved to do that job - it's a delicious house.
But I think I would have steered things in a different way.'
Newhailes is not the only disappointment of his professional life. Much of his early career was spent working on St Paul's Cathedral and Norwich Cathedral, and he admits to a 'long-held ambition to look after an English cathedral'. In 1994 his wish was granted when he was appointed surveyor of the fabric of York Minster. The following year, after a change of dean, he relinquished the post at the request of the new incumbent.
Sometimes presented as a reactionary conservationist, he protests: 'I like Modern architecture, but I don't really understand modern materials, that's not my line; but I greatly respect people who do.' His objections are actually more serious than issues of style and relate to changes in building technology brought about by the Industrial Revolution.
Clearly, James Simpson represents an important generation of architects who, like many members of the public, find it hard to forgive and forget the errors of the past, and still less accept the destructive hand of Modernism as 'heritage'.
'It is very hard to remember that back in the '60s there was an assumption that all old buildings would be demolished - it really was assumed that by the end of the century there would be hardly any old buildings left.'
That there are so many, and in such good condition, is due in no small measure to the efforts of an army in which Simpson has been a significant force.
While battles remain to be fought, one ambition remains above all others. In spite of having worked on many houses associated with William Adam - Arniston, Yester, Hopetoun, and Tinwald - it remains his greatest dream to secure a future for Mavisbank, very much on Historic Scotland's 'Buildings at Risk' list. A model of Mavisbank sits in his office as a constant reminder.