It is not a paint, but a material made of carbon nanotubes – Kapoor’s particular version is sprayable – that allows for no shadows or demarcations. According to its creators, if a watch were coated in Vantablack, it would appear as a black hole on one’s wrist.

“If you put it on a fold, you can’t see the fold. So my proposition is that this material is therefore beyond being,” Kapoor told Wallpaper magazine.

He also dismissed the row over its use as a “ridiculous controversy”. 

However, it was a controversy that Kapoor seemed to delight in stoking.

Kapoor accused of monopolising the material

The creator of London’s ArcelorMittal Orbit and the “Bean” in Chicago enraged his fellow artists when he signed his exclusive deal in 2016.

Christian Furr, a British painter, said at the time: “I’ve never heard of an artist monopolising a material. This black is like dynamite in the art world.

“We should be able to use it. It isn’t right that it belongs to one man.”

Another British artist, Stuart Semple, went further. Likening Kapoor to “kids at school who wouldn’t share their colouring pencils, but then they ended up on their own with no friends”, he brought out a pigment that he described as “the world’s pinkest pink”.

It was available for sale online, priced at just £3.99, with buyers required to tick a box confirming that they were not Anish Kapoor or his affiliate, and “to the best of your knowledge, information and belief this paint will not make its way into the hands of Anish Kapoor”.

Kapoor then took the playground spat to another level by getting hold of the pink, posting a picture on Instagram of his middle finger dipped into the pigment, and captioning it: “Up yours.”

Semple responded by bringing out his own “blacker than black” acrylic paint, the latest version of which he sells for £99.99 per litre.

Vantablack was developed by Ben Jensen of Surrey Nanosystems. Scientists at Nasa were trying to create their own version, but Jensen beat them to the punch.