Is it a slide... is it a work of art? Or is it a lucrative rescue mission for London’s very expensive Olympic artistic legacy?

'I really like the dirtiness of it and the confusion it creates,' says Carsten Höller, 'that you don’t really know what it is, but that it truly creates a unique experience.'

The artist is talking alongside Anish Kapoor as the first pieces of his new stainless steel slide are pieced together at the base of Kapoor’s own sculpture, the ArcelorMittal Orbit. Last year, the Belgian artist accepted an invitation by Kapoor to wrap a corkscrew slide around the Orbit, created for the 2012 Olympics. Höller accepted, and in June the spindly, steel-framed red scribble in the sky over East London will become the world’s longest, tallest, twistiest slide.

It's nine years since Höller’s Test Site slides delighted audiences in the Tate Modern Turbine Hall. The installation 'experiment' tested audience’s reactions to five different slides. Höller wanted to show that you don’t necessarily get to know a sculpture better by literally travelling through it; that once inside it begins to look like something else entirely. He's also interested in the unique states that humans have when we let go – 'somewhere between delight and madness', as he puts it. 

The Slide, a permanent fixture at London’s Olympic Park, will give people a full 40 seconds to experience this and decide for themselves as they make their way down the 178m chute at an estimated 15mph. 

In a purely formal sense, says Höller, you can see The Slide as 'two spirals' coming together. 'I like to use the term grafting that you use in horticulture – you put one thing on top of another and it starts to grow and function together without becoming totally mixed up,' he says.

It sounds natural and straightforward when put like that, but the reality of seeing the slide, surprisingly slim and elegant with its 60cm diameter and 3mm walls, growing beanstalk-like around Kapoor’s precariously unsymmetrical sculpture, is an undeniably thrilling and intimidating prospect.

Both Kapoor and Höller say they are expecting people to criticise the artwork for being an 'attraction'. They make no secret of the fact that the idea of turning Kapoor’s sculpture and viewing deck into a crowd-pleasing pull was the Mayor of London’s idea. When asked about his inspiration for the artwork, Kapoor replies : 'Boris Johnson – how can I put it – foisted this on the project, and kind of insisted.'

'No artists ever made a fortune from a public sculpture, I can assure you. Isn’t that true?' says Kapoor turning to Höller, who smiles conspiratorially.

'We’re holding out hope for the future.'