Tony Blair has said he regrets not keeping a diary, in a podcast interview with actor Stephen Fry.
Tony Blair said politics was undergoing 'fragmentation'
Mr Blair is likely to be offered millions for his memoirs when he leaves Downing Street later this year.
But publishers will not be able to draw on a detailed record of his private thoughts during his 10 years in power, the prime minister has revealed.
The diary kept by his ex media chief Alastair Campbell has long been the subject of speculation at Westminster.
Extracts were read out during 2004's Hutton Inquiry, but
Mr Campbell insisted it was not intended for publication, despite claims it would command a hefty advance from publishers.
Asked by Mr Fry, a longstanding Labour supporter, whether he wrote a diary, Mr Blair responded: "No, I don't."
The actor pointed out that Mr Blair at least has a record of his working life in his official diary to help him when writing his memoirs, and he replied: "I know, but I often wish I had the discipline to keep one."
Mr Blair said he had not given much thought to what he would do when he leaves office. "The trouble is, when you are doing the job you are so much in it ... you don't have time really to think ahead," he said. "But as the time approaches I will have to, so I will," he said in the podcast on the Downing Street website.
He also revealed he did not carry a laptop computer in his ministerial red box, unlike his Cabinet colleagues.
Mr Blair said he expected to "devote a lot of time" learning about computers when he leaves Number Ten.
But despite his self-confessed technophobia, he urged politicians to use new media to reach out more to voters.
He also spoke of the difficulty of conducting "meaningful policy debate" in a highly-competitive media market place.
"The most difficult thing in fact...is that there is this interaction between politics and the media today that is very difficult because the media is highly, highly competitive," said Mr Blair.
While he said he was not criticising the media, he said it "works by impact ... and the biggest impact will come from scandal or controversy or pictures that make a visible impact."
He said it was difficult to have a "reasoned policy debate" unless it was communicated in "sufficiently newsworthy terms" for press and television.
He said politicians needed to accept that not every person was interested in the same subjects - "therefore you have got to tailor the manner of your debate".
"If you take a young person and their political interest today, there is no point, in my view, in the Labour Party or the Conservative Party, any political party, engaging those young people at the level of thinking that they are as interested, for example, in National Health Service reform, which people tend to get to somewhat late in life."
He said young people would more likely be interested in the environment or Africa, "or, you know, career opportunities in new technology industries which is something that they will have a particular fascination for.
"And therefore this fragmentation is meaning that the world of politics has to operate with different mediums and different points in time."