The portrait was one of a several of Madonna painted by Howson
An oil painting depicting Madonna in the nude with her ex-husband Guy Ritchie has failed to meet the reserve price of £15,000 at auction in Glasgow.
Acclaimed Scottish artist Peter Howson has produced several portraits of the pop icon in a state of undress.
Madonna & Guy was painted in 2005. The couple parted last year.
The portrait, being sold by a private collector, did attract some bids during the sale at McTear's Auctioneers but they did not satisfy the seller.
Brian Clements, director at McTear's Auctioneers, said: "The auction was very successful, however, surprisingly Peter Howson's controversial piece Madonna and Guy did not sell on the day.
"The painting is still for sale and we would be delighted to hear from anyone who is interested in this much talked about piece of Scottish art history."
In the painting the singer is reclining and film director Ritchie has a hand on her thigh.
What began in 2000 as a fairytale wedding at Skibo Castle in the Scottish Highlands came to an end in November when the couple were granted a "quickie" divorce.
They share custody of their two boys, Rocco and adopted son David Banda.
The McTear's Scottish Contemporary Art Auction also featured a host of other works by former official war artist Howson.
Controversial nude portraits of Madonna painted by the Scottish artist were exhibited at a small gallery in Ayrshire in 2002.
Howson was offered substantial sums to open the collection in New York, Paris, Los Angeles or Italy.
But he rejected the approaches in favour of the Maclaurin Art Gallery in Ayr.