Clive James says terminal illness and confronting his mortality have given him the clarity to focus like never before.

The prolific writer and Australian cultural icon was diagnosed with leukaemia in 2010 and is battling terminal emphysema - a condition that prevents him returning to Australia.

In a candid one-hour interview with Kerry O'Brien, James speaks openly about his writing, his broadcasting career, and looking death in the eye.

"I won't see Australia again, and it weighs on me. I'm very sad about that," he said.

The interview, which O'Brien says left James physically exhausted, was filmed in the Old Library at Pembroke College in Cambridge, where the 73-year-old studied in the early 1960s.

James reflects warmly about his time at the university alongside the likes of Germaine Greer and Eric Idle.

He also talks with remarkable honesty and his trademark humour about the prospect of his looming death.

"I won't be buying a ticket to Switzerland so I can book into some clinic and pay people to put me into a long, deep sleep. I can get that from television here," he quipped.

"The truth is I've got almost everything wrong; my lungs are in bad shape ... I have to have my immune system replaced every three weeks," he said.

'Death is a subject'

As an author, poet, essayist, and journalist, James's literary achievements are as broad as they are impressive. That's not to mention his years as a broadcaster and television host.

He is currently working on the sixth volume of his memoirs, and earlier this year released a translation of Dante's Divine Comedy - a project that was a decade in the making.

James says his illness has added an extra dimension to his writing.

"Bad health makes you think," he said.

"Approaching death is a subject. Writers love subject. I'm writing things now that I never would have written before.

"Just before I got sick I was having illusions, fantasies, that I was world-weary and I'd had enough of life and it wouldn't matter very much if I disappeared [and] I'd done it all - all that self-indulgent stuff.

"Those feelings vanished overnight as soon as I got sick and I just wanted to live.

"I've found this period when I have been ill, as I am now ... I find it brings a clarity of mind and the ability to concentrate on the essential that I never had when I was well. When I was well I was so energetic I never noticed anything."

Love, marriage and separation

James, who has gone to lengths over the years to shield his family's private life from the media, discusses the early days of his romance to Prue Shaw, his wife of 45 years.

The pair have been separated since last year, a period which has been difficult for the ailing writer.

O'Brien has interviewed James a number of times, but says this was the first time they discussed his personal life in any detail.

"It's the first time we have quite consciously gone into that personal exploration," O'Brien said.

"This time, because he has written quite explicitly in two or three poems about where he is in his personal life, I felt like I had the licence to go there.

"Clive, as reflected in his recent poetry, is feeling that sense of being in a solitary place. I think quite clearly, reading between the lines, he would like to be back with his wife Prue."

James speaks fondly of his younger days with Shaw, a Dante scholar who showed him the finer points of the Divine Comedy.

"She showed me how the verse worked and immediately I was enthralled. It was a big thing for me; it was a big thing for me and her. In fact it's still a romance that is still in a way going on 45 years later," he said.

"I should say that: we are still married and still involved, but you don't get more involved than when you are reading something together."

James's quality as an artist 'never in doubt'

Despite the sombre subject matter of their discussion, O'Brien says it is one of the most satisfying interviews of his career.

"The thing about Clive James is that he is an original mind with the boldness to chance his arm at all kinds of things and the end result is there for all to see," he said.

"He is now recognised globally as a poet of high quality. He's recognised as a great writer of prose. He's recognised as a humorist. He's recognised globally as a satirist. He's recognised as somebody who was a terrific songwriter – the fact that his songs never took off is another matter.

"The quality of his work was never in doubt and it's been true of everything he has taken on."