These are confusing times in the business of protecting the country’s architectural heritage. Certain structures are deemed worthy of preservation forever, at a hidden cost of hundreds of millions, as Grade I listed buildings. Other works, with equal claim to respect, are denied protection and cast into oblivion. ... Recently, two large modernist buildings were up for consideration for listing: the British Library in St Pancras, and an East End council estate, Robin Hood Gardens. ... Both have benefited from changes of aesthetic wind. The MPs’ judgment of the library now looks bizarre. The interior is airy and uplifting and benefits from a quality of finish and detail that, in public buildings, now seems to belong to a bygone age. The gnarled concrete of Robin Hood Gardens is also beginning to look more appealing, compared to the flat-pack panel construction of modern blocks of flats.

For many years, middle-class homebuyers have been discovering postwar council estates such as Golden Lane in the City of London and the Trellick Tower in north Kensington. They turn out not to be the hellholes of legend, but thoughtfully designed. Robin Hood Gardens has an obvious asset, in a central, mature landscape around a picturesque mound, and more subtle qualities of proportion and rhythm.

In the eyes of architectural historians, Robin Hood Gardens is equal to, if not greater than, the British Library. Its architects, Alison and Peter Smithson, were intellectual leaders of international renown, whereas the library’s designer, Colin St John Wilson, was more a skilled follower of others’ ideas. Yet the library has been granted the immortality of a Grade I listing, while the estate has been denied recognition and is set to be demolished. The listing of buildings is meant to be about their “historic and architectural significance”, by which criteria the two buildings are equally worthy of listing.

An obvious difference is that people live in Robin Hood Gardens, many of them disadvantaged, and that preserving the knotty old work can be seen as an obstacle to the betterment of their lives by its demolition and replacement. The views of architectural historians won’t be of much interest to them.