But in the event, they were beseiged. "We were really surprised," says the Society's Gill Sack. "I could have filled two coaches." Indeed, such was the response that the Society are thinking of repeating the tour. For, in the wake of the loft-living Nineties, in which interiors have rejected chintz, ornamentation and cosiness in favour of glass, steel and clean furniture lines, there has emerged a huge appetite for modern architecture and design, with its angular vocabulary of glass and concrete.
Until recently, it was assumed by the popular press that such Modernist buildings were not only anathema to the British love of the beamed and inglenooked, the thatched and the quaint, but also had contributed in a basic way to the downfall of society. While we were happy to admire the Sears Building in Chicago and stay in huge functionalist rectangles on holiday, these hard-edged monstrosities were just not for cosy old Brits. Picturesque was us.
But now, people are queuing for the sort of refurbished offices, light industrial buildings and new-build schemes that are either Modernist originals or that take their cue from the tradition. One of the developments on that 20th Century Society tour was Goldfinger's listed Alexander Fleming House, a welfare office turned loft warren in London's Elephant and Castle district, now named (in typically bogus New York-ese) as Metro Central. "Ten years ago, people were moving to the suburbs and doing one-hour commutes,"says Paul Vallone of Berkeley Homes. "But now many people want to live in the city-centre environment, and their interiors have changed to reflect that urban aspect. They are much more conceptual and design oriented."
Berkeley is doing several similar developments in London and Birmingham, but they are no longer confined to the city. In Burscough, Lancashire, where Fairclough Homes has its new Priory Park development - on the exterior a conventional development with half-timbered frontages and pitched roofs - show homes have been dressed up with steel banisters, glass stair treads and textured glass doors, which let light filter throughout the interiors.
These developments show a mushrooming style fed by industrial chic, cinematic Americana and white-walled Euro-Modernism. Out with the tudor beams and coaching lamps; in with the glass-brick wall, the iron girders and metal staircase. "It used to be location, location, location," says Vallone. "Now it's design and lifestyle."
A new generation has emerged, believes Elain Harwood of the 20th century listing department at English Heritage, who not only want the excitement of the city, but also crave an appropriately urban style to go with it. "Perhaps it is a reaction to the countryside becoming more suburban, or that Modernist buildings are becoming part of history, which means it's okay to like them," she says.
"It's to do with the 'brick is boring' and 'space and light is good' approach," says Roger Zogolovitch, who has teamed up with fellow architect Will Alsop to create a new-build residential loft-type development in London. "That has its fashion aspects to it, but the fact is that housing is a consumer item." This had led to what Zogolovitch calls the Calvin Klein advert-type loft cliches. But so be it. They are still a move away from "these little boxes that don't suit anyone. Consumers are more sophisticated when they are given a chance," he says. "They seem to want imaginative space that reflects new building technology."
But inevitably, as the modern becomes more popular, it also becomes more dilute. The present idea of Modernism is a different, softer thing altogether than those conceived by the Modern Movement. Some of the more purist members of the Twentieth Century Society, for example, have objected to the way that Alexander Fleming House has been refurbished. "It's obviously better still to have it," says Sack, "but we're not particularly pleased. It's too cosy and soft. We feel it is a compromise."
Nor has any of the intellectual content of the Modern Movement, so crucial in the pre-war period, filtered through to much of the new generation, for whom it may well be a fad, a designer tweak. Alternatively, the next few years could be the first era in which modernity truly hits the mass market.