An artist today completed the last portrait of First World War veteran Henry Allingham before his death at the age of 113 as the world's oldest man.

Dan Llywelyn Hall, 28, painted Mr Allingham following a single sitting earlier this month in his room at St Dunstan's care home for blind ex-service personnel in Ovingdean, near Brighton, East Sussex.

Mr Allingham, who was Britain's oldest surviving First World War veteran, died at the home on July 18, prompting tributes from across the world, including from the Queen, Gordon Brown and the Prince of Wales.

The painting, measuring three-and-a-half feet by two-and-a-half feet, was completed using oil and acrylics and shows a pensive-looking Mr Allingham gazing downwards dressed in a white shirt and cravat.

It is expected to be exhibited in a gallery in Covent Garden, central London, from November before being put up for sale, with proceeds going to St Dunstan's.

Mr Llywelyn Hall said today: "I offered to do the portrait because I was intrigued and inspired by the things I had read and heard about him.

"I felt I had a duty to portray an image which would be a memento. Throughout the sitting, he was cheerful and singing along, he was a very amusing bloke.

"When I heard about his death, I did alter the picture and it now has more of a pensive quality. It was a huge privilege to be able to paint him."

Mr Llywelyn Hall enquired about painting Mr Allingham after completing a portrait of fellow First World War veteran Harry Patch, 111, the last surviving Tommy, which is on show this month at the National Portrait Gallery.

Cardiff-born Mr Llywelyn Hall graduated in illustration from the University of Westminster in 2003 and splits his time between Cardiff and London.

As well as the National Portrait Gallery, his work has also featured at the Imperial War Museum.

A public funeral with military honours will be held for Mr Allingham next Thursday at St Nicholas Church in Brighton.