One of the most fascinating things about tech- nology is its apparent irreversibility. The Pharaohs had geometry, mechanical engineering and project management down to such a fine art that they could keep a workforce slogging away at a pyramid for 50 years or more using the same materials and methods.
We have a problem adhering to any masterplan with a programme as long as five years. As a result we could not contemplate building an accurate replica of an Egyptian pyramid. On the other hand the general idea of turning the clock back and doing things the old fashioned way, is a project that appeals to a lot of people.
Propose rebuilding Old Saint Paul's for instance, or Whitehall Palace or Nonsuch and the cry will go up 'When can we start!'
Alas, the real question should be, 'what will we end up with if we do?' For invariably - as numerous stainless-steel bolted, rain screen-clad copies of Palladio's Villa Rotunda attest - by the time modern methods, fire regulations and security systems have succeeded in twisting the arms of even the most dedicated replicators, only a soft- focus lens from a quarter of a mile away will make the result look convincing. This is because the problem with replication is not so much a matter of appearance as it is of method.
Take an easier example than a pyramid or a palladio. At the end of the Second World War some 150,000 prefabricated houses were built for local authorities in England and Wales. They were not exactly a rarity then, and a few of them survive in use to this day. But to build a new one to its original specification today would be all but impossible.
Even the simplest one, the arcon, had a hot- rolled steel angle frame, welded tubular-steel roof trusses, a prefabricated 'Denham' plumbing unit in copper, steel, brass and cast iron; pull switches everywhere and roofs and walls clad in asbestos with only a miserly 15 mm of insulation. The sole space heater was a small 'slow combustion' solid fuel stove that heated the water too.
So primitive does this dwelling sound from this description that we might be excused for thinking, from the comfort of the rotating 'captain's chair' in our Mercedes Z Class, that anybody could knock one up in a weekend. But they couldn't. A replica arcon house, authentic in every detail, asbestos cladding, ungalvanised lead painted window frames and all, would be nearly as impossible as a 40-year contract pyramid.
Oddly enough the problems of authenticity do not diminish very much even if you leap nearer to the present and think in terms of producing a replica home counties bungalow from the 1960s.
The first shock you would encounter would be finding out, as Robert Adam explained in his paper 'Tin Gods and Contemporary Architecture', that more than 30 materials basic to the appearance of such a building had already been replaced by synthetic substitutes by the end of the 1980s.
Painted cast iron rainwater goods had given place to self-coloured plastic; softwood single-glazed windows to double glazed upvc; bitumens to polymers; linoleum to vinyl; floorboards to chipboard; joints in roofing timbers to nail plates, plaster to Artex, distemper to emulsion and so on.
The only solution to this crisis of irreversibility lies in investing the term 'replica' with a degree of flexibility. And this of course is what we do. In the art world our inability to really replicate leads to the manufacture of fakes - which are new things made to appear old. In the world of architectural conservation it leads to compromise in the shape of old buildings restored until they look new - under halogen bulbs of course.