Pest Control

If you own a Banksy print, the single most important thing about it after the print itself is its Pest Control certificate, because without one the major auction houses won't sell it, most serious dealers won't buy it, and every price on this site stops applying to it. It's worth understanding what the certificate is before you buy, and before you ever need to sell.

What Pest Control is

Pest Control Office is the body Banksy set up in 2008 to deal with the business of authenticating his work, and it is the only organisation that can say whether something is by him. It was set up because the market was filling with fakes and with street pieces cut out of walls, and because an artist who stays anonymous can't turn up in person to vouch for his own work.

When Pest Control confirms that a work is genuine, it issues a certificate of authenticity for that specific piece. The certificate is tied to the work itself rather than to the owner, so when the print is sold, the certificate goes with it.

What a certificate looks like

The detail everyone remembers is the banknote. Each certificate has half of a Di-Faced Tenner attached to it, the fake ten-pound note Banksy printed with Princess Diana's face in place of the Queen's, torn in two. Pest Control keeps the other half. Because every tear is different, the two halves can be matched to prove the certificate is real, which makes it very hard to forge convincingly.

The Di-Faced Tenner is also a work in its own right, and signed sheets of them come up at auction, which is a nice circle: the prop that protects his other work is collectable too.

Why auction houses insist on it

Sotheby's, Christie's, Phillips and Bonhams will only offer Banksy works that come with a Pest Control certificate, and most of the specialist houses follow the same rule. For a buyer that is a large part of the point of buying at auction, because the house has done the checking and the certificate is part of what you are paying for.

We looked at this in our own data, out of curiosity. Across the auction record, lots whose descriptions mention the certificate sold for almost exactly the same as lots whose descriptions don't mention it, about 1% more. That isn't because the certificate doesn't matter. It's because nearly everything that reaches a major auction has one already, whether or not the catalogue bothers to say so, and the prints without one never get into the record at all. That's also why the Collection won't value a print without a certificate: the results on this site simply don't describe what an uncertificated print is worth.

If your print doesn't have one

Pest Control will look at a work that has never been certified, using a form on its website that asks for the history of the piece: where it came from, when and how you acquired it, and any paperwork you have. It charges a fee for the process and publishes the current rates on its site. It will only authenticate works that were made to be art, which means prints, paintings and sculptures, and not stickers, posters, currency or pieces removed from the street.

If you are buying, the rule is simple. Ask to see the certificate before you commit, check that the title and edition number on it match the print in front of you, and be very wary of anyone who says the certificate is on its way or has been lost. A genuine print with a certificate is worth what the results on this site say, and the same print without one is worth a great deal less, even if it is exactly as real.

If you are unsure what your print might be worth once it is certificated, its page on this site shows every result and our current value, and the one for the unsigned Girl with Balloon is a good example of how much of a difference a certificated record makes, with more than eighty results behind it.