Berlin built a lot of suburbs in the inter-war years. Take the U-Bahn to the south-eastern outskirts, get out at Parchimer Allee, and the first thing you’ll notice is that Mock Tudor villas are nowhere to be seen. Instead, the view is of rows of flat-roofed, low-rise apartment buildings, outlined in dramatic colour schemes – blue, red, white, yellow, with large balconies and the doors and windows emphasised with contrasting colours. They’re all submerged in dense, and public, greenery, rather than placed behind paved-over front gardens.

Walk for a few yards along a long red block of flats and you come to two flanking community buildings, asymmetrical and angular, and a large flight of steps leads you down to a sweeping, horseshoe-shaped crescent with a pond at its centre, as dramatic in its way as anything in Bath. This is the Berlin-Britz Housing Estate, better known after that central crescent as the Hufeisensiedlung, or “Horseshoe Estate”, and both aesthetically and politically, this suburb is a very long way from Ruislip or Edgbaston.

When you walk along the long red block to that horseshoe, however, you can see opposite some rather different housing – this time with much more muted colours, white with a little sky-blue to the doorways, Biedemeier-style details, dormer windows, shutters and big, deep pitched roofs. This is because Berlin-Britz is one of those few places where a political and architectural dispute were played out in a very direct way – with modernism and traditionalism literally pitted against each other. This was already controversial, though, as the largest scale modernist housing project that had happened anywhere at that date – housing not the rarefied clientele of Le Corbusier’s then-celebrated modernist villas, but a population of working class Berliners.

The estate is one of those few places where a political and architectural dispute were played out in a very direct way

Facebook Twitter Pinterest The view from the centre of Bruno Taut and Martin Wagner’s Hufeisensiedlung. Photograph: Iain Masterton/Incamerastock/Corbis

The Horseshoe Estate housed 3,000 members of GEHAG, a building society set up in 1924 by Germany’s trade unions, with the assistance of the Social Democratic party, and headed by party member, architect and planner Martin Wagner. They selected as their architect Bruno Taut, a committed socialist and utopian architect, obsessed with the chromatic properties of applied colour and tinted glass. Low budgets meant there wasn’t much of the latter, so Taut concentrated his energies on outlining these simple, ordered, brick-built modernist flats in increasingly wild and dramatic colours. They were then let or sold to members of the GEHAG, usually trade unionists, usually skilled workers.

The estate opposite was built by DEWEGO, another building society, this one set up by white-collar unions; their architects, Engelmann and Fangmeyer, favoured something a lot more traditional. This happened when the German press – not just architectural – was caught up in the “flat roof debate”. For the German right, flat roofs were un-German – Mediterranean, Arabic, most likely Jewish; the pitched roof was German, indigenous. For the Nazis, this was a matter of racial characteristics, where the pitched roofed house had a German “face”, and the physiognomy of modernism was “degenerate”. The attacks weren’t all one-sided – Taut and the GEHAG also had contempt towards the folkish fantasies of their opponents, and that long block that divides the two estates was nicknamed the “Red Front”.

Here, then, is an opposition that would be influential, if not always accurate, in the way modern architecture was perceived – in short, socialist, modernist and working class v conservative, traditional and middle class – and one that had real political consequences. In 1933, the new Nazi government immediately dismissed Wagner from his job as planner of Berlin; Taut fled to the USSR, and from there to Turkey.

In this debate, and in this housing estate, the purists and the bigots were the traditionalists, not the modernists

However, on the ground, the differences between the two estates are not so obvious. Stylistic detail aside, both are a distinctive central European version of the garden city idea, with flats instead of houses, and lush communal areas surrounding them rather than private front gardens. The differences are not in what the buildings do (both were social housing, in flats, in the suburbs), but what their form says about the city, about modernity. While the DEWEGO estate is just a series of pretty, slightly cutesy blocks of flats, the Horseshoe Estate, as suburban as it undoubtedly was, was also a statement of confidence in the future, and in social possibility, with each part of it closely related to the other, around those verdant communal spaces.

Taut and Wagner’s estates – this is merely the largest of five major projects of the late 1920s - were granted Unesco World Heritage Site status in 2006, and most have been well restored. However, they have few real heirs; by the mid-1930s, modernism had developed into an almost classical, white-walled abstraction that left little room for Bruno Taut’s experiments in colour.

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The Horseshoe Estate was not modernism as a style, but as a new way of life – a vision of humanised technology, tamed nature, and a modern, confident, social, communal approach to the city. And right at the heart of it, just past the horseshoe, is a diamond-shaped green – with, around it, two pitched-roofed terraces.

For the other side in the flat roof debate, roof shape was a matter of life and death, a marker of racial purity. But for Taut and Wagner, as these terraces indicate, it was something they were happy to experiment with according to site and preference. In this debate, and in this housing estate, the purists and the bigots were the traditionalists, not the modernists.

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