Hundreds of art lovers have braved snow and freezing temperatures for the chance to buy artworks by some of the country's top creative names for just £45.
Some had been camping outside the Royal College of Art (RCA) since Tuesday for the Secret Postcard Sale, which features miniature works by designer Sir Paul Smith, Wallace and Gromit creator Nick Park and artist Julian Opie.
An RCA spokeswoman counted 50 tents outside the site at Battersea, south-west London, as of Friday night, and said there were at least 300 people queueing when the doors opened at 7am on Saturday.
But even those at the front were taking something of a gamble on getting their hands on a famous artist's work as the designs are all anonymous, with signatures on the back only being revealed after purchase.
Film director Mike Leigh, Stone Roses guitarist John Squire and inventor Sir James Dyson also donated works to the sale, but buyers will have to spot these out of 2,700 other designs.
This is the 20th year of the RCA sale, and organisers hope it will raise more than £120,000 for a fund to support emerging artists.
The event has made more than £1 million for artists' grants and bursaries since it was established.
Artists who have previously given works to the sale include Yoko Ono, Anish Kapoor and Tracey Emin.
Wilhelmina Bunn, RCA Secret curator said: "We're thrilled with the number and quality of postcards that have been sent to us this year.
"The breadth of artistic styles make a visually stunning exhibition, with contributions by artists and designers from all walks of life displayed next to each other."