A portrait of Winston Churchill that the former Prime Minister infamously loved could fetch over £100,000 at auction.

The artwork, drawn by artist Paul Trevillion in 1955, was the only portrait that Churchill ever signed, making it a very valuable piece.

Mr Trevillion was just 21 when he drew the pen-and-ink portrait of his hero.

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The artist's sketch, which depicted the wartime leader with a jovial grin and a glint of fun in his eyes, is said to have brought a smile to Churchill's face.

The World War Two leader, who was born at his family's ancestral home, Blenheim Palace, in Woodstock, was so impressed with the portrayal that he summoned Mr Trevillion to his door to sign it.

The portrait will be auctioned by Hansons Auctioneers on Wednesday, November 20, in the month marking the 150th anniversary of Churchill's birth on November 30, 1874.

It is hoped the artwork will attract bids in excess of £100,000.

Mr Trevillion, now 90 and living in Tottenham, London, hopes the portrait will fetch more than £1 million, the figure it was insured for when displayed at Manchester's National Football Museum in 2017.

He plans to donate some of the proceeds to good causes, including the Peace Field Projects, a children's football charity, and the Churchill Foundation.

He said: "Unfortunately, Churchill's birthday was ruined by the Sutherland portrait, so I decided to do another portrait for his next birthday.

"My drawing was based on images I'd seen of Churchill when I was a child in the Blitz.

"I was five years old when war broke out in 1939.

"Churchill was always smiling, with his famous V for victory sign.

"Those images of him helped me cope with the night-time raids."

Mr Trevillion managed to get his portrait delivered to the then-retired politician via Bernard Sunley, a friend of Churchill's and a client of designer Lazslo Hoenig, for whom Mr Trevillion was working at the time.

He was surprised to receive a phone call from Churchill himself, inviting him to meet at the Bernard Sunley Buildings in Berkeley Square.

Mr Trevillion said: "When I walked into the room, Churchill was seated.

"He put out his hand.

"I went to shake it, and he held it.

"He said he was expecting someone much older."

Churchill signed the picture, telling Mr Trevillion: "There have been a lot of portraits painted of me, but this one I really like.

"It's the only one I've ever signed."

Neil Barker, manager of Hansons' Churchill150 Auction, said: "We are privileged to offer this wonderful work.

"It is arguably the most important Winston Churchill portrait in existence."