The generosity of artist Rolf Harris is about to bring one couple a cash windfall years after a kind deed.

Viv Ayres met Rolf years ago when the majorette troupe she ran, The Bluebirds, was invited to appear on the BBC TV gameshow, The Generation Game.

Retired school cook Mrs Ayres, 66, and husband John, 70, a retired bus driver, formed The Bluebirds troupe in Maidstone in 1974, quickly building a reputation for entertaining the crowds wherever they appeared. Word of their success reached the BBC and the invitation to appear on The Generation Game followed.

Rolf was booked for the same show, to paint one of his enormous pictures, and to Mrs Ayres’ delight he presented her with the painting as a keepsake reminder of the occasion.

It is inscribed “To The Bluebirds, nice memories of the Generation Game August 1981, with love, Rolf Harris” and his signature cartoon self-portrait.

“The problem was the size of the picture,” Mrs Ayres said. It’s nearly seven feet wide and two feet deep and we didn’t have a wall big enough to display it.”

Ever since, the painting - of two Aborigines in a canoe on a moonlit night - has been kept carefully rolled up and stored.

But now Mrs Ayres and her husband Jon have decided to sell it.

“It’s time our painting went to someone with the space to display it and appreciate it,” Mrs Ayres said.

It will go under the hammer at The Canterbury Auction Galleries on Tuesday March 24. It is expected to sell for up to £600.