Richard Wilson's 20:50 exhibition is spellbinding

Charles Saatchi is notorious for his eternal thirst for new art, and his sometimes ruthless sale of it.

But there are some works which have remained in his collection for many years, and Richard Wilson’s installation 20:50 (1987) is perhaps the most visible example.

It was a permanent fixture at Saatchi’s space in Boundary Road in north-west London before being one of the few artworks to sit comfortably in his disastrous County Hall gallery.

Its new presentation at Saatchi’s Duke of York’s HQ confirms that it is one of his best acquisitions.

20:50’s effects begin as you enter the building — a smell of petroleum hits you which, by the time you’re in the basement room which the work occupies, is almost intoxicating.

You enter the room on a platform and are confronted by a bright space whose walls, ceiling, windows and views outside are mirrored in an tranquil pool of recycled engine oil (which gives 20:50 its name).

Initially you look down onto the work, before descending on a walkway into the heart of the installation, with oil surrounding you at waist height.

The work is characteristic of Wilson’s activities. He makes technically complex interventions into architecture, which often appear effortless and often dramatically change our reading of space.

Despite having seen 20:50 several times, I still find it spellbinding. This time, as I stood at the core of the installation, immersed in the interplay between the real room and its mirror image, I became disorientated — I felt as if I was hovering between the spaces.

The new presentation is not perfect — the entrance platform allowing visitors to look down onto the work denies you the intimate encounter with the installation which was possible at Boundary Road, where you were alone in the room.