Biba, the face of 1960s and early 1970s fashion, was named after its moving spirit, the fashion designer Biba (Barbara) Hulanicki.

From its first small premises in Abingdon Road, High Street Kensington, London, in 1964, it quickly moved to bigger premises in 1965 and then, in 1969, to a couple of shops next door to each other and knocked through to make one showroom at the bottom of Kensington Church Street.

The shop was dark; it was stylish; it was cutting edge fashion with a retro feel; it was boas and Twiggy and maroon velvets and floppy hats and it was hugely successful and influential.

In 1974 it moved into the seven floors of the old Derry & Toms department store back in Kensington High Street, but the huge scale of the new building rather overwhelmed the old Biba feel, and this was also a time of economic turbulence.  In 1975 it closed.

Profile of a woman in front of the Spanish Garden in the Roof Gardens at Kensington.

The Kensington Roof Gardens in London are the largest roof gardens in Europe.  They were originally constructed for customers of the fashionable, and now defunct, department store Derry and Toms (later Biba) in Kensington High Street, which was built in 1932.

The Anish Kapoor mirror sculptures (forms, really) are still in their positions in Kensington Gardens and this week I walked past the one which curves in and upwards to a point from a circular base, called Non Object (Spire). 

As always, there is a short, young, clean-shaven man, well wrapped up, guarding it.  It occurred to me that the man is much more interesting than the sculpture.  It is not only that he is a living creature; there is something intriguing about the idea of him spending every daylight hour fixed in this spot, alone, only fiddling with his iPhone, and not always even that.  What are his thoughts?  How does he while away those long hours? 

I went up to the sculpture, which had its polished mirror surface spotted with rain drops.  I said to him “Does the rain damage the sculpture?”.  But he was turned away from me, wrapped in his hooded, padded jacket; and could not see me; or, apparently, hear me.  I imagine he had headphones on underneath the hood. 

So I did not even hear his voice - and the mystery remained intact.