We’ve all known for a while that some previously hated Sixties concrete architecture was coming to be regarded with affection, especially by the cognoscenti. After all, English Heritage has been listing buildings of the period for years, and conservationists are now as zealous in their attempts to preserve them as they used to be about Victorian railway stations. But Monsoon shows that “historic” modernist architecture can now command reverence bordering on awe. This successful company could have moved anywhere it wanted. And it did, but not the way you’d expect. It chose to buy, restore and convert the derelict, long-abandoned Paddington Goods Yard Maintenance building, which looms over the elevated urban motorway of the Westway like an ocean liner.

The result is electrifying. This was a building designed, in the early 1960s, with the then unbuilt motorway in mind. It’s in love with the motorway: one curving wing slides underneath it, another virtually kisses it. At its prow are two heroic funnels. It is set on a rising bend in the road - from which, it seems to be sailing towards you, on a collision course. It would be inconceivable for such a building to be built today. It would not be allowed to come so close to speeding vehicles that, from inside, you can make direct eye contact with the drivers. The staff restaurant is right by the road. It’s called, with dark humour, “Bangers and Crash”.

Its original architect was Paul Hamilton, of the practice Bicknell and Hamilton. Today, it has been rejuvenated by a new generation: notably Ceri Davies of former Young Turks, now successfully established, architects Allford Hall Monaghan Morris. Some of their own work - notably the pierced oval concrete canopy of their recent Walsall Bus Station - harks back to this period. But here they were dealing with a real, glorious, period one-off.