On a windy Saturday morning last June, Didier Pasquette stepped off the roof of a tower block at Red Road in the North of Glasgow on to a high wire some ninety metres above the ground, and began to walk towards his target, the next block of flats on the estate.

With a long pole to aid his balance, but none of the safeguards you might expect - no net to catch him, no harness to hold him - Pasquette took tentative, oddly graceful steps into the void between the two buildings, watched by a small band of local residents.

The skywalker wasn’t taking this unconventional stroll to add to his list of record-breaking tightrope stunts - in the past he’s crossed the Thames, 30 metres above the flowing river, and walked the length of the pitch at the Stade de France in Paris - but at the behest of artist Catherine Yass.

For Yass, Pasquette’s daredevil passage between the towers of Petershill Drive marked the realisation of a work she has spent years developing, revising and bringing into being.

‘I first had the idea for this work, or some kind high wire work, in 2002,’ she explains, ‘but I never really thought it would be possible. So, for a long time, it was a dream about a dream: I was dreaming about this walk through the air, which is something people do dream about, and is a wonderful, fantastical thought.’

That flight of fancy has come to fruition in the form of High Wire, a four screen video piece recording Pasquette’s walk with accompanying photographs, which premiered last night at the CCA, a centrepiece of the Glasgow International festival of visual art.

But why film a tightrope walk, and why film it here in Glasgow?

High Wire is the latest in a strand of lens-based works by Yass that focus on the built environment. All deceptively simple, each one of these brief filmed pieces is a close examination of a single site, with roots in Yass’ ongoing investigation into the real-world outcomes of Utopian idealism, often tempered by personal concerns. For the 2002 piece Descent, which earned Yass a Turner Prize nomination, the artist slowly lowered a crane-mounted camera through a fog-bound Canary Wharf construction site. Wall traced the contours of the barrier between Israel and Palestine in unforgiving close-up, and, most recently, Yass trained her lens on the passage of a ship through the Three Gorges Dam on the Yangtze river, an engineering marvel that displaced millions of Chinese citizens, for Lock.

‘I’m looking for concrete manifestations in the world for things that are very much intangible,’ Yass explains, ‘You’d hardly say that Canary Wharf was built from some great Utopian ideal, but it was built on an ideal of capitalism, the wall in Israel was built as a result of a movement which had once been idealist, and in China at the moment there is this great celebration of capital, and that’s become their Utopia, as far as I understand it.’

The meditative, almost elegiac quality of Yass’ film installations masks, then, a distinctly ambivalent view of the structures she films. They are also more than dry essays on the relationship between man and his surroundings. ‘I wouldn’t have done any of them if there wasn’t a strong personal element,’ Yass admits, ‘Wall, for example, had a lot to do with thinking about how your own mind can get blocked up, how you can create barriers in your own mind, and not think imaginatively around the corners of things.’

These two sources of inspiration - the public and socio-political matched with the private and personal - dovetail neatly in High Wire, with the fantasy of walking in the air allied to what Yass calls the ‘social dreams’ expressed in the high-rise architecture of the Red Road development. ‘I was thinking about dreams and fantasies and what happens when we try to put them into reality,’ she says, ‘In this case, that was with respect to Modernism and Modernist architecture - these towers were maybe built with a sense of Utopia, and later people began to see the problems with them - and the dream of walking through the air. Then there’s the relationship between that dream which might be very personal, and a social dream.’

For those who lack a head for heights, viewing High Wire might well be less a dream, more a nightmare. The four projected loops - three track Pasquette’s progress from different angles, the fourth is a view from the skywalker’s head-mounted camera - combine to form a vertiginous vista that is little short of terrifying.

Watching it on a small computer monitor in Yass’ London studio, I found myself hanging on to the arms of my chair as if my life, or Pasquette’s, depended on it - blown up to three by four metre projections, High Wire ought really to come with a health warning.

And then, well, there’s a twist. Something happens, something which Yass has asked me not to reveal, preferring that visitors to the installation find out for themselves. Suffice it to say that, while Pasquette’s walk in the sky did not - thank goodness - end in tragedy, nor was it an unqualified success. ‘My heart,’ says Yass of this unexpected turn of events, ‘was in my mouth.’

This unforeseen incident flags up something of a shift in Yass’ practice. For, while High Rise follows the precedent set by earlier pieces in terms of its central themes, it is the first time the artist has added a human actor to her work; where before her moving cameras were always precisely constrained, attached to cranes, tracks, and, in one case, a remote control aeroplane.

‘In all of these works, the camera has become the eye, and in that respect this one is no different,’ Yass says, ‘But what happened when we actually did it - what made it interesting in the end, what made it the project what it is - happened because the camera was on a person and not a machine.’

That human element resurfaces in the photographs that complete the High Wire installation. Yass has enlarged negative prints of the Red Road blocks and mounted them on light boxes, having painstakingly scratched the surface of her original negatives, marking out the lines of the high wire rope. As with the restraint shown in the filmed work, an apparently simple gesture stands in for a densely layered set of concerns.

‘If you’re printing a negative,’ Yass says, ‘It always has the potential to become something other than itself. It’s on the way somewhere, rather than being something very final. We think of photography as indexically recording something, but you can think of it as a kind of drawing - Fox Talbot called photography the ‘pencil of nature’ - so I was interested in linking drawing and photography, and was thinking about architects plans, where again we have that transformation from one thing to another.’

In the end, transformation might be the key to understanding the work of Catherine Yass: she has transformed a private dream into a public spectacle, and transformed the spectacle into a work that, ultimately, seeks to transform our understanding of the structures that surround us.

This feature was first published in The Herald in March , 2008.