POLICE raids on libraries have – in Britain at least – been few and far between. But in July 1940, the Met decided that a Hampstead reading room was an obvious place to find enemy aliens.

The Germans and Austrians who had arrived in Britain over the previous decade were, after all, mainly of an intellectual bent. In a bitter irony, most were also refugees from the Nazi regime: Jews, communists, social democrats, “degenerate” artists or some combination of the lot.

In The Alienation Effect, Owen Hatherley makes the case that Central European émigrés changed Britain for good. Not only through their presence and vast cultural output – spanning art, architecture, film, publishing and journalism – but in how they made us see ourselves differently as well.

The book’s title is inspired by the Verfremdungseffekt of Bertolt Brecht’s theatre, which renders “what would otherwise seem normal and uninteresting into something strange and unnatural”. In other words, says Hatherley, “the aliens made us all a little bit alien too”.

The undisputed centre of the émigré world was Finchleystrasse – as bus conductors used to announce when arriving on Finchley Road. Here in Swiss Cottage you could find the Cosmo Restaurant, or Louis’ Hungarian Patisserie – which lives on in its smaller offshoot in Hampstead Village.

In this quiet corner of middle-class London, the Hungarian Soviets, Red Vienna and the Weimar Republic found a new life. Not always finding acceptance in the establishment institutions of London, it was from here too that cultural revolutionaries and reluctant reformists spread their ideas as far as Ullapool and St Ives.

It was on Downshire Hill that Fred Uhlman – a “second-rate Expressionist-lite painter” and “superb if hardly prolific writer”, according to Hatherley – set up the Free German League of Culture. John Heartfield lived in Uhlman’s house for five years, before settling in Highgate. The photographer and spy Edith Tudor-Hart was to be found in a studio on Haverstock Hill, while her sister Beatrix was neighbours with the academic and Soviet intelligence recruiter Arnold Deutsch and the art historian Hans Hess at the Isokon in Lawn Road.

All of the above were communists or fellow travellers – bringing a continental class consciousness to their bourgeois environs.

But Hatherley is equally attentive to the liberal and avowedly apolitical figures who found acceptance – for a time – in the British establishment, such as the architectural writer Nikolaus Pevsner, the art historian EH Gombrich and the free market economist Friedrich Hayek.

Hatherley is admirably sober in judgment – patiently explaining the revolutionary nature of émigré architecture while meticulously analysing why much of it no longer stands. He offers a dry humour, too. The works of Berthold Lubetkin – including Highgate’s High Point, Finsbury Health Centre, Bunhill’s Bevin Court and the penguin pool at London Zoo – are “the most famous and most celebrated buildings of their time in Britain, and with the exception of the pool, which the penguins have long vacated, the most successful with their residents and users”.

Given the quality of his research and analysis, is hard to think of The Alienation Effect as anything but a magnum opus. But physically, it is one of the heaviest books around, even for a 600-page hardback. Perhaps it’s the high-quality paper, but its sheer weight means it’s hard to read in bed – and yet hard to read anywhere apart from at home.

Hatherley is at his best when he balances his encyclopaedic factual architecture with his folk-punk dreaming. In one brilliant tangent, he imagines the Dadaist artist Kurt Schwitters “barking out” his poem London Symphony “over a blaring one-chord drone, once again turning shit into gold”.

But the prose can get heavy, too – specifically, and somewhat ironically, in the long sections discussing the 1930s revolution in paperback book design, led by the likes of Leipzig’s Jan Tschichold and Berlin’s Hans Schmoller at Allen Lane’s Penguin Books. The Alienation Effect is published by – you’ve guessed it – Allen Lane, an imprint of the modern Penguin Random House.

The émigrés, Hatherley concludes, “were often not so interested in merely importing something into their new home”, but were instead inclined “to take their ‘Weimar’ and remake it into something useful for a reformist, social-democratic or socialist reorganisation of Britain”.

Many would be disillusioned by the capitalist Wild West created in their wake, and – in architecture and planning at least – explicitly framed as a reaction to their ideals.

It’s now broadly recognised that the Britain they left behind – from Finchleystrasse to Newport and East Tilbury – is a far richer landscape than that they encountered when they arrived on its shores.

• The Alienation Effect: How Central European Émigrés Transformed the British Twentieth Century. By Owen Hatherley, Allen Lane, £35