Banksy explains why and how he destroyed artwork that had just been sold for £1m

Banksy has revealed how he secretly built a shredder into a painting so it would self-destruct moments after being sold for more than £1m.

The anonymous street artist posted a video on Instagram showing Girl with a Balloon being sliced into strips at a Sotheby’s auction.

He claimed that the preparations were carried out “a few years ago” and defended the stunt with a quote from Picasso: “The urge to destroy is also a creative urge.”

Banksy’s video begins with the caption: “A few years ago, I secretly built a shredder into a painting ... in case it was ever put up for auction.”

An unidentified person in a hoodie is seen installing the sharp blades in the frame of the picture.

The video then cuts to Sotheby’s as the auctioneer begins taking bids for the artwork, rising from £100,000 through £400,000 before ending on £860,000, which, taken together with the buyer’s premium, made a final total of £1m.

As the hammer goes down to confirm the sale, the crowd cheers – only for the frame to emit a bleeping sound as the painting is shredded.

Banksy did not explain how the device was activated.

He celebrated the prank with a post on Instagram with the caption: “Going, going, gone...”

Sotheby’s senior director and head of contemporary art, Alex Branczik, said: “It appears we just got Banksy-ed.”