When Sir Harry Evans gives public talks on the importance of good clear writing, he likes to play a video of Japanese subway workers shoehorning desperate commuters into peak hour trains.

The legendary British newspaper editor sees the antics of Tokyo's famous white-gloved Oshiya, or "pushers", as symbolic of one of the worst sins a writer can commit — trying to cram too much into one sentence.

"The digital age has made communication so much easier. But it's led to a great deal of confusion and verbosity," he says.

Sir Harry is terminally frustrated that writing, an art form that can be so simple and beautiful, can so easily be turned into impenetrable sludge.

"The convoluted language which is typical of business leaders is so wasteful of our time," he says.

"One of the reasons why reading can be tiresome is because people who have been doing the writing have been more concerned about their own egos than the receiver of the words."

The former editor wants to help anyone guilty of polluting the page with what speechwriter Don Watson refers to as "death sentences".

Sir Harry believes the origins of "post-truth" society emerged from post-modernism. ( Wikimedia Commons: Grace Villamil )

After over 70 years in journalism and publishing, Sir Harry has distilled all he has learnt about writing and editing into a form guide for crafting simple sentences, 'Do I Make Myself Clear — Why Writing Well Matters'.

"When I was editing The Times or The Sunday Times, the important thing was first of all to find out what the hell was going on, but then to express it clearly so the meaning was unmistakable and it was as concise as possible," he said.

'Fake news' a threat to individual freedom, dignity

As Sir Harry writes in his latest book, words have consequences for everyone.

"The bursting of the housing bubble that led to the Great Recession revealed that millions had signed agreements they hadn't understood or had given up reading for fear of being impaled on a lien," he says.

The 89-year-old has had plenty of practice honing his craft — he started out as a newspaper reporter in Lancashire in the 1940s.

As a foreign correspondent for The Guardian in the 1950s, he travelled through the deep south in the US covering the birth of the civil rights movement.

He returned to the UK determined to bring back the kind of campaigning journalism that had thrived in city and regional papers in the US.

After he took over as editor of The Sunday Times in 1967, his reporters broke a series of big stories.

Sir Harry became editor of The Sunday Times in 1967, after which the paper broke a series of big stories. ( ABC News: Steve Cannane )

The newspaper's Insight team exposed the treachery of Soviet spy Kim Philby, and uncovered the appalling treatment of children who had suffered birth defects from the drug Thalidomide.

It also conducted a ground-breaking investigation into what happened during Northern Ireland's Bloody Sunday massacre.

As editor of The Sunday Times between 1967 and 1981, one of his mantras was: "It's no use publishing the truth once, it has to be part of a long-running campaign."

Sir Harry now fears we live in an era where those who tell the truth are facing a campaign to discredit them.

"We live in testing times. If you read the history of Europe in the interwar years, in Italy and Spain and so on, you see the first thing those in power wanted to do was to diminish faith in the media," he says.

"Now we see this new invention called 'fake news'.

"It is an attempt to remove one of the barriers protecting the freedom and dignity of individuals, and any of those individuals so credulous to believe it are actually betraying themselves."

The 'post-truth' era has deep roots

While Sir Harry is scathing of US President Donald Trump's attack on journalism, and anyone who buys into it, he believes the origins of the so called "post-truth" society emerged from post-modernism.

"Its roots are much deeper than Trump. Its roots are in the rejectionists, the relativism started by French sociologists suggesting that all truths are relative," he says.

"Now we have the Tea Party movement's chief spokesman on the record as saying there's no such thing as facts."

The veteran newspaperman moved to the US in 1984. As he watched last year's Brexit debate from across the Atlantic, he felt British voters were exposed to similar doses of misinformation.

During the referendum campaign, key Brexiteer and Conservative minister Michael Gove attacked economists and others who questioned the benefits of leaving the EU, by saying, "people in this country have had enough of experts".

Sir Harry describes the comments as "appalling".

"I'd like to say to them, next time you're having an operation, I'm going to send my carpenter in to do the surgery," he says.

"He's not an expert, you understand, so I think he will be perfectly acceptable to you.

"Those morons are trying to deny centuries of advancement in education, science, research and independence, nibbling away at civilised standards. They are the real enemies of the people."