Image copyright Jeff Overs/BBC Image caption John Humphrys: "You are not answering the question"

Once described as "the listeners' champion", John Humphrys has spent 32 years grilling interviewees on the Today programme.

On Thursday he is stepping down from BBC Radio 4's flagship news show as its longest-serving presenter.

His forensic approach is feared by politicians of all stripes, although his combative style has also made him a divisive figure.

He can even claim to have played a part in ending the career of his own boss - the then BBC director general George Entwistle in 2012.

In a bruising encounter with Humphrys following a Newsnight report which wrongly implicated former Tory Party treasurer Lord McAlpine in a child abuse scandal, Mr Entwistle was forced to admit that he had been unaware Newsnight was broadcasting the allegations.

Within 12 hours he had resigned, after just 54 days in the job.

Image copyright Press Association Image caption John Humphrys interviewing former prime minister Tony Blair in 1997

Humphrys interviewed the former prime minister, Tony Blair, a number of times throughout his political career.

In Mr Blair's final interview with his long-time interrogator, he said: "Despite all the tussles we've had over the years, I respect the fact that you're good at your job and you're on top of the facts.

"The fact that I worry about doing an interview with you is a tribute to you - not a criticism."

Media playback is unsupported on your device Media caption John Humphrys interviews George Entwistle on Newsnight crisis

Former Conservative deputy leader Lord Heseltine describes being interviewed by Humphrys as "a gladiatorial contest".

"He's out to catch you, you're out to make your points," he says.

The Tory grandee faced Humphrys countless times as a minister under Margaret Thatcher and later as deputy leader under John Major.

During that time he developed a few strategies for dealing with him.

"It's very important to know what you wanted to say. Usually I would have my answers written down on a piece of paper, waiting for John's questions," he says.

"The trick was knowing how to fit the answers into the questions."

Lord Heseltine admits this approach was not always successful.

"You knew when I was in trouble because I'd say, 'John, you've asked the wrong question, the question you should have asked is this'," he says.

"And then before he could get a word in, I would try and answer the question I wanted to be asked."

When he was able to successfully fend off Humphrys' blows, Lord Heseltine says this prompted great amusement from BBC colleagues.

"If John had not won on a knock-out, often the interview was followed by peals of laughter from the BBC studio," he remembers.

Media playback is unsupported on your device Media caption Lord Heseltine clashes with Humphrys during 1995 Tory leadership race

Tory MP Jacob Rees-Mogg has found the best tactic is to try and answer questions as directly as possible.

Now Commons leader, he has also been interviewed by Humphrys in his previous role as chair of the pro-Brexit European Research Group.

"He won't let you get away with a woolly answer - he's very ruthless at coming back to people who haven't answered the question," he says.

"So you find you might as well just answer the question first time round. There's no point in beating about the bush because you will find the bush turns out to be a burning bush."

As foreign secretary under Tony Blair, Jack Straw had his fair share of quizzing by Humphrys, particularly over the Iraq War.

In 2005 he found himself defending the government over advice it received on the legality of the war - just 10 days before a general election.

"It was extremely difficult," he remembers. "John's a fast bowler - in that sort of situation you're very rarely going to score a six or a four, the important thing is just to protect your wicket."

For particularly tough interviews Mr Straw says he used to have a clock in front of him to keep track of how long he had to keep going for - although this could be scuppered if the editor decided to let the interview run over time.

Image caption Jack Straw: "He was there to do a job - to put ministers in power on the spot"

Nevertheless, Mr Straw says in some ways he preferred Humphrys' direct style of interviewing.

"People say that he's a rottweiler. What I felt about him was he was there to do a job - to put ministers in power on the spot," he says.

"I enjoyed the challenge and the opportunity to put across my point of view - being confronted by defects in your arguments and hopefully having an answer to those."

However, Humphrys' interviews have not been immune from criticism.

Image copyright Getty Images Image caption Emily Thornberry: "He felt it was his role to be the voice of the public"

Some argue that frequent interruptions can prevent interviewees from finishing their points and be counterproductive for the listener.

Shadow foreign secretary Emily Thornberry says that while it is important to press politicians for answers, sometimes Humphrys can take it too far.

In 2017 she criticised an interview with shadow justice secretary Richard Burgon, where she claimed the BBC presenter interrupted and "sneered" at every answer he gave.

"As a politician you tend to go onto the media when you have a message you want to get across," she says.

"That's when it can be frustrating if you're interrupted or the subject is changed."

At times, she says, Humphrys' aggressive line of questioning can miss the mark. In particular, she cites a 2016 interview with Labour MP Angela Eagle where Humphrys asked whether she was a suitable candidate for party leader because she had cried during a radio interview.

Media playback is unsupported on your device Media caption Angela Eagle: I'm not crying now

However, Ms Thornberry also recognises his ability to hold politicians to account and "reflect the frustrations of the public", particularly in the pre-social media age.

"I think Humphrys comes from a time where this was one of the few ways the public could interact with politicians," she says.

"He felt it was his role to be the voice of the public."