An artist who unveiled his latest work at the Great Yorkshire Show is aiming to raise thousands of pounds for the Yorkshire Air Ambulance.

John Mackie, who lives in Haworth, has produced a picture of "Haworth by the Moonlight", which he hopes will raise more than £3,000 at auction. In addition, there are 250 signed limited-edition prints available for sale at £295 each.

Mr Mackie, 50, has been painting for more than 40 years, specialising in portraits and landscapes, and has exhibited his work worldwide. Last year he was commissioned to paint a portrait of the Queen, which is now displayed in Buckingham Palace.

The commission was arranged through local businessman Lee Clayton, who wrote to the Palace informing them of Mr Mackie's offer to produce a portrait of the Queen, an offer which was readily taken up by the Palace.

It is intended that the portrait will eventually be donated to one of the Queen's charities.

Mr Mackie said: "I'd heard about the air ambulance and when a friend was airlifted to hospital after an accident I wanted to support this vital service and a painting seemed the obvious way.

"Many artists have portrayed Bront country's beauty but I thought I'd revert to my early days of painting in Glasgow at night with my miner's lamp, so I decided to capture Haworth by the moonlight."

Yorkshire Air Ambulance fundraiser Paul Gowland said: "This is an extremely generous gesture by John.

"To have a painting commissioned just for the charity is a real honour.

"John is highly regarded in the art world and I'm sure that art lovers and air ambulance supporters alike will jump at the chance to own one of his masterpieces."

The Yorkshire Air Ambulance, which is based at Leeds/Bradford Airport, has been saving lives across the county since October 2000.

It has been scrambled more than 2,700 times, carried about 460 patients to hospital and treated more than 620 injuries on scene.

With a maximum speed of 140 mph, it can fly patients to hospital in minutes.

Prints of the painting can be obtained from the service's charity office on 0845 120 60 60.