An art gallery has had to destroy hundreds of prints of mock stamps showing the Queen wearing a gas mask.
The Royal Mail said James Cauty's pictures infringed its copyright
The Royal Mail said the pictures, which had been on sale at artrepublic in Brighton, breached its copyright.
Three images, showing first, second and third class stamps, had to be taken off display in June after the Royal Mail first complained.
Artrepublic management said it has lost "thousands of pounds" by having to destroy the prints which it would have been trying to sell.
'Thousands of compliments'
The artworks were created by former pop star James Cauty, who was in the group KLF, and were a reflection of his stance on the war with Iraq.
They first went on show in the gallery, in Brighton's North Lanes area, in May.
Artrepublic was commissioned to sell 450 but said it has only sold about 10 of them, leading to the heavy financial loss.
When the Royal Mail first complained in June, gallery owner Lawrence Alkin said: "I am quite amazed. It has had a fantastic reception.
"We have had one or two objections and thousands of compliments."
A Royal Mail spokesman said: "We do take any breach of copyright very seriously, especially in relation to the Queen's image."