“It’s important if you are running a political party, which I did for almost eleven years and the country for six years, the process of communicating is incredibly important.”

That’s what David Cameron told me when I interviewed him for the new Sky documentary Feral Beasts about the relationship between prime ministers and the media.

Important it may be, but prime ministers and their media advisers, sometimes called spin doctors, are usually reluctant to talk about how they try to manipulate us journalists to get their message across to you, the voting public.

We took the title Feral Beasts from a bitter speech about the press which Tony Blair chose to deliver at the end of his decade in Downing Street in 2007.

In it, the prime minister attacked the media for hunting in packs, seeking to tear everything apart.

Watch ‘Feral Beasts: Prime ministers and the media’ on Sky Documentaries at 9pm tonight and on Sky News at 9pm tomorrow

Two things struck me as we carried out the interviews for our film.

Firstly, the five living UK prime ministers share a general resentment about how they were treated by the media when in power.

Secondly, that our most recent prime ministers, Theresa May and Boris Johnson, have not been prepared to subject themselves to the sort of bruising encounters that Margaret Thatcher, John Major and Gordon Brown regarded as just part of the job.

Boris Johnson has done hardly any full-length interviews and often tries to use social media to bypass journalistic scrutiny completely. The public loses out because what he says cannot be tested or challenged directly.

Alistair Campbell, Mr Blair’s chief media handler, explained: “Tony used to relish doing difficult interviews because they were often the way of getting the message across.”

Mr Blair told us: “Personality and having a character today that’s interesting to people; that is a big part, a much bigger part of politics than in my day.

“And because there’s not that in-depth dive on policy in the same way that there used to be, it’s [the case that] you can be an entertainer and win. Is that something the public really want? Is that all they are being given?”

Mr Blair believes that the public will realise that it is paying “a price for the entertainment as the key question in political leadership”.

When the mood shifts, he wonders if today’s political media will be in a position to respond.

He said: “Has it become so changed by social media and by the need to just chase after every passing news wave that it finds itself without the capacity to offer what the public wants?”

It is true that the Blair government stuck to a programme of interviews and regular open-ended news conferences.

New Labour’s media experts Peter Mandelson and Alastair Campbell were also prepared to play tough to get their message across.

“We wanted to be proactive. We wanted to feed the beast,” Lord Mandelson explained.

“So we were framing things, offering stories, making announcements.”

But Labour’s media management came a cropper following the invasion of Iraq, when its repeated claims and dossiers of evidence that Saddam Hussein had weapons of mass destruction turned out to be wrong.

From that moment on, prime ministers and their press handlers became more defensive and less preoccupied with getting a clear message across through the media.

Gordon Brown, Tony Blair’s successor, cut back on media relations.

“Gordon felt throughout his time that the media didn’t rate or respect his intellect, his knowledge and depth, he felt the media were shallow and superficial,” according to Lord Mandelson, who became one of his advisers.

Mr Brown’s unease as a media performer was on full show in an open mic incident during the 2010 General Election campaign, when Sky News broadcast him calling Gillian Duffy, a woman he’d just spoken to on the campaign trail, “bigoted”.

After a spirited campaign mounted by Sky News, Gordon Brown and David Cameron, by then the front runner, made the brave decision to take part in Election Leaders’ Debates, joined by then Liberal Democrat leader Nick Clegg.

This was the only time they have taken place properly in this country, before or since, even though the research showed that the public felt better engaged and informed by the debates.

Prime Minister David Cameron emulated New Labour by hiring high-powered media secretaries.

First Andy Coulson, the former editor of The News of the World, who had to quit when he became embroiled in the phone-hacking scandal.

He was followed by Craig Oliver, a former ITV and BBC news producer – the first person from TV to hold the job.

Mr Cameron embraced the control element of New Labour, not the openness.

He avoided regular news conferences and cut back on interviews. He took a back seat in two referendums for which his premiership will be remembered, on Scottish independence and EU membership.

The ‘No’ campaign won in Scotland, but Mr Cameron resigned after Leave defeated the Remain campaign, which he was nominally heading.

Craig Oliver believes the media should share the blame.

“Do I feel that the Leave Campaign played fast and loose with the truth?” he says.

“Yes. Do I think broadcasters handled themselves in glory in terms of actually working out what was going on? No.”

Katie Perrior, media adviser to Theresa May, admitted to us: “Behind the scenes it was difficult.”

She was never comfortable with that side of her role and avoided it. When I mentioned that I had not interviewed Mrs May much when she was in Number 10, Ms Perrior retorted: “Because we wouldn’t let you, Adam.”

Boris Johnson is also not keen on the traditional sit-down interview with well-briefed political journalists.

He prefers to stage photo-opportunities in which he is the star, often in a comical costume.

Social media was just getting into its stride when David Cameron was elected. He put out a few video clips on “Webcameron”, but to his regret soon abandoned the idea.

He also tried to hire his own press photographer but had to let him go almost immediately, after an outcry that independent photographers should do the job.

Today Boris Johnson has several photographers and a TV camera team on the government payroll, producing daily pictures and videos for social media – entirely under Downing Street’s control.

Press photographers are now not invited to some events.

A top photographer, Stefan Rousseau, pointed to a recent incident to explain why they should be included.

“Boris Johnson visited a hospital in Northumberland, and one of the papers made a big deal out of the fact that he wasn’t wearing a mask,” he said.

“And that was only shown because there was a wire agency photographer there. If you look at the pictures on Flickr issued by the government that day, there wasn’t a single picture of him not wearing a mask.”

Commenting on this prime minister’s hiring of his own team of image takers, David Cameron remarked ruefully that Mr Johnson can get away with things which ordinary mortals can’t. We shall see.

Watch ‘Feral Beasts: Prime Ministers and the media’ on Sky Documentaries at 9pm tonight and on Sky News at 9pm tomorrow