The portray shows the duo in a state of undress with Madonna reclining on a green throw while Ritchie stands behind her with his hand on her upper thigh. But after the bitter divorce battle between the pair earlier this year, the portrait was put up for sale by its current owner at McTear's auction rooms in Glasgow.
While 17 other Howson works found new homes in the packed house of art collectors, his artwork featuring the former couple failed to fetch its lower guide price of 15,000 pounds.
"The auction was very successful. However, surprisingly, Peter Howson's controversial painting of Madonna and Guy Ritchie did not sell on the day," the Scotsman quoted a McTear's spokesman as saying. "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," the spokesman added.