When a collage of digital images was sold in New York earlier this year for £50 million, the art world was convulsed. The reason? The picture couldn't be hung on a wall and was only visible online.

What had been bought and sold was the non-fungible token - or NFT - relating to the collage. David Aaronovitch and his guests discover how NFTs work for those who sell and those who buy them and also consider if NFTs are a passing fad or an aspect of our culture that is becoming increasingly common and might lead to the emergence of a future John Constable or Tracy Emin, eventually spreading to and influencing other art forms.

Enter the Briefing Room and find out why collectors are investing in NFTs; how easy it is to spot a fake and what you can do about it; and whether non-fungibles will be an enduring part of the artistic - and investment - worlds in the years ahead.

Those taking part include: Georgina Adam of The Art Newspaper; investor in NFTs and co-founder and chief executive of the Arts and culture portal Vastari, Bernardine Bröcker Wieder; and the art historian, former art dealer and presenter of the BBC FOUR series, Britain's Lost Masterpieces, Bendor Grosvenor.

Producers Simon Coates and Bob Howard

Image: Visitors to "Machine Hallucinations - Space: Metaverse" by Refik Anadol, which will be auctioned online as an NFT at Sothebys, at the Digital Art Fair, Hong Kong