At the moment, he is hoping the Chinese not only buy his books but some of his paintings also.

At Christie's in London on June 28 he is selling some of his art collections, including French impressionist works by Monet and Brouillard, beloved by many Asian buyers.

The conservative estimate of the works up for sale is 7.5 million pounds.

"I think the serious Chinese collectors will want Brouillard because he is under-priced and I am hoping they turn up for that. The Chinese are arguably the biggest buyers in the market at the moment and many of them are from the mainland," he says.

Archer, who has a disciplined writing regime of four periods of two hours a day, the first starting at 6 am, produces everything by hand.

"I don't know how to use a computer. I know that people think it is mad. My wife has promised to buy me an iPad for my birthday and show me how to use it," he says.

He is currently driven by his latest project, which he describes as a pentology, and which he expects to complete by 2016 at the latest. It was almost a 70th birthday challenge.

"Terrific focus challenge, isn't it? Five books. Don't worry about anything else. Focus on it and do it," he says.