What is the best piece of mid-20th century urban design in Birmingham?
According to Andy Foster, author of the Pevsner Architectural Guide to the city, it is the work of the architect James Roberts on Smallbrook Queensway in the city centre.
Roberts designed the building on the corner with Horse Fair which contained the Scala cinema, and next to it the 230 metre-long office building which sweeps along the ring road.
It bridges over Hurst Street, and ends close to Debenhams. Roberts (born in Birmingham in 1922) is also the architect of the Rotunda but Foster reckons his Queensway building, completed in 1962, is his best work.
Smallbrook Queensway was the first part of the Inner Ring Road to be built, in the late 1950s.
Unlike later phases, which treated the Inner Ring Road rather like an urban motorway, ruthlessly separating it from buildings and pedestrians, Smallbrook Queensway was designed as a street.
It has pavements on either side, enclosed by buildings with shopfronts at street level.
For this reason, in 1959 it was criticised by the eminent head of the Birmingham School of Planning, Leslie Ginsberg, as being old-fashioned. But Ginsberg got it completely wrong.
Smallbrook Queensway has survived and prospered whereas, since 1988, the rest of the "concrete collar" has been recognised as the damaging and alien barrier that it is and been subject to demolition and reshaping.
Roberts' Queensway building is a grand and elegant urban gesture. Its curvature on plan and sweeping horizontal lines, its rhythm of vertical fins, together with its characteristic projecting concrete uplighters, make it still the most impressive piece of modern streetscape in the city, even 54 years after its completion.
It is directly comparable with the work of John Nash in the early 19th century, when Nash cut the curving new boulevard of Regent Street through a tangle of lanes and alleys in London and lined it with elegant neoclassical commercial buildings.
But the Smallbrook Queensway building is now threatened by a redevelopment proposed by its owners CEG (Commercial Estates Group).
CEG proposes to demolish the section between Hurst Street and Horse Fair, including the bridge over Hurst Street, and to rebuild it as residential apartments. A tower of at least 22 storeys is proposed on the corner with Hurst Street (CGI above).
The section of the building between Hurst Street and the Bullring is proposed to be stripped back to its concrete frame and rebuilt, with two additional floors of offices added on top.
Nothing of the original character of Roberts' building would survive this redevelopment. The architecture of the proposal is bland and unexceptional, lacking the distinctiveness of the existing building.
The developer claims the continuous sweep of Roberts' building is maintained in the new proposal but this is not so as can clearly be seen in the published images.
The removal of the bridge link, and the addition of the tower on the corner, would severely interrupt the flowing line of the street.
The developer maintains the demolition of the bridge section is necessary "to provide clear and legible views between New Street station and Southside/China Town".
But passing under a bridge does not reduce legibility. If it did, we would probably have no town gates in the walls of towns like Ludlow and Chester, and no railway viaducts.
In fact, gateways like those, and that on Smallbrook Queensway, actually assist legibility: they are landmark places which frame views and help people find their way about.
The main motive for the proposed redevelopment is the existing offices fall below the standards which businesses now expect and are therefore difficult to let. This is clearly an economic problem which requires action.
But is the proposed redevelopment the appropriate action? A comparison with James Roberts' 1965 Rotunda is instructive.
Twenty years ago, offices in the Rotunda were also not performing well economically and the enterprising developer Urban Splash's 2008 conversion of the building to residential use, designed by architect Glenn Howells, certainly changed the appearance of the Grade-II listed building.
Howells consulted James Roberts and his redesign retained the essential characteristics of the original. It was done with the approval of Roberts and obtained listed building consent.
I am sure it is possible for a good architect similarly to upgrade the Queensway building and produce office suites of a high quality, with better access and thermal performance standards, without destroying those qualities that make its architecture outstanding, just as Howells renovated the Rotunda.
Having James Roberts' best building statutorily listed as of architectural importance would certainly encourage CEG to do this.
It is likely the 20th Century Society will make an application for listing and Historic England (previously English Heritage) will consider it seriously.
CEG intend to submit a planning application in April. All too frequently, Birmingham's planning committee and planning officers appear not to recognise the architectural quality which the city possesses.
One admirer of Roberts' building is the author and film-maker Jonathan Meades, who last week told me: "Birmingham's appetite for self-destruction is boundless. It is especially crass at a time when the singular merits of 1960s architecture are at last being widely acknowledged."
CEG's high-rise building is yet another proposed tall building which is not in the council's tall building zone, outside of which tall buildings are discouraged.
The council's policy states that "tall buildings should not be located in areas where they disrupt an existing coherent townscape of merit".
In fact, this proposed tall building and the rest of the redevelopment, would disrupt the best piece of mid-20th century urban design in Birmingham.
It will be interesting to see if the council will follow its own policy and not allow the quality of the public realm to be sub-ordinated again to a developer's own interpretation of its commercial interests.
Joe Holyoak is an architect and urban designer