Cameron, Blair and Dame Edna join Humphrys' final Today programme
John Humphrys was joined by ex-prime ministers David Cameron and Tony Blair - and Dame Edna Everage - for his last day on BBC Radio 4's Today programme.
A characteristically tough interview with Mr Cameron began with the former PM thanking him for "striking the fear into politicians like me".
But the host aimed a parting shot at politicians who do not allow themselves to be scrutinised on shows like his.
Meanwhile, Dame Edna penned a poem that joked about retirement.
The flamboyant entertainer, created by Barry Humphries, called them both "national treasures", adding: "You won't grow old, you'll just get nicely mellow/So hug your trees, play Elgar on your cello."
Humphrys has left the flagship morning news programme after 32 years. Closing the show, he thanked his colleagues, saying: "My apologies if I was just a teeny bit grumpy."
He also thanked listeners, adding: "I do hope you keep listening. Today matters for tomorrow. And if that's a rather corny way to end my years on the programme, then so be it."
Mr Cameron said the presenter had made his career out of "asking us questions we don't always want to answer, and calling us to account".
The former leader's comments came after Humphrys put it to Mr Cameron that he had "misled the nation" by failing to deliver on the result of the 2016 EU referendum, by leaving his post in government.
Humphrys has built a reputation as a tenacious if divisive interrogator, and said he had been "a seeker of truth" during his time on the programme.
Earlier on Thursday, Mr Blair took part in a discussion about the state of interviewing and politics. "The fact that I worry about doing an interview with you is a tribute to you, not a criticism," he said.
Their interviews were "often a pleasure", he said, adding: "It was occasionally not a pleasure but it was always worthwhile."
Humphrys has interviewed every prime minister on the programme from Margaret Thatcher to Theresa May. However, he pointed out that Boris Johnson had not appeared since he came to power, while Labour leader Jeremy Corbyn had stayed away for almost three years.
"Increasingly, politicians are talking directly to the people via social media so they can choose the questions they answer without being challenged," he said.
In his closing remarks, Humphrys thanked those he had interviewed, "including the politicians, or at least those of them, the vast majority, who still recognise it is important that people in power should be held to account, even if just occasionally we might give them a hard time".
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The presenter quipped that Thursday's political guests had "been just a little overshadowed" by Dame Edna.
Her poetic tribute began: "We national treasures have but one requirement, and that is to give deep thought to our retirement."
Dame Edna continued: "How I loved to hear you sing when you and I had that tempestuous fling/But I've always been discreet about our lives and I've never breathed a word to your ex-wives."
Another guest was the new chief executive of the Woodland Trust, Dr Darren Moorcroft. Humphrys asked about punishments for people who chopped down trees - but joked that he was dissatisfied with the answer.
"I was thinking of something a little more draconian - send them to jail if they chop down trees, that kind of thing," the presenter said.
Dr Moorcroft replied: "That may be your next job John if you become a judge at the Supreme Court." Humphrys added: "You're on - accepted."
Thought for the Day, delivered by Rabbi Lord Jonathan Sacks, was also about Humphrys and his "fearless moral passion".
BBC director general Lord Hall appeared, and told him: "Thank you to you on behalf of all of us - the people who have loved working with you, the people who have put up with you at times as well."
He added: "In all the stuff you read in the papers about the Rottweiler Humphrys and all that stuff, you are also someone who handles interviews with people who have been through traumas or disasters, or have something they want to get off their chests but don't know how to do it, with amazing sensitivity."
Today will continue with four main presenters - Justin Webb, Mishal Husain, Martha Kearney and Nick Robinson - and will not directly replace Humphrys.
He reminisced with current and former co-hosts at the end of Thursday's programme. Asked whether he really was someone who regularly interrupted interviewees, he replied: "Of course I am. Well, I'm an arguer. I love arguing."
His colleagues recalled an occasion when he destroyed the last typewriter in the office. "There is a bit of a myth about me throwing it out of the window. There may have been a little small incident involving it, but I did not throw it out of the window."
The 76-year-old will continue to present Mastermind on BBC Two.
He is Today's longest-serving presenter and has been one of the corporation's highest earners. His salary in 2016-17 was between £600,000-£649,999, but he took a pay cut and went down to £290,000-£294,999 in 2018-19.
Six of Humphrys' most memorable (and controversial) interviews
- He said his first interview with a prime minister - with Margaret Thatcher in 1987 - was "a truly scary prospect". But he showed his knack for getting insights into politicians' characters when he asked about the link between her Christian faith and her politics. "How can you express unselfish love if you have no choice?" she said. "The fundamental choice is the right to choose between good and evil."
- Cabinet minister Jonathan Aitken accused Humphrys of "poisoning the well of democratic debate" in 1995 after saying he had interrupted then Chancellor Kenneth Clarke 32 times. But Humphrys got support from other ministers and the Daily Mail, which called him "one of the most brilliant journalists in the country". The next time Mr Clarke appeared on Today, Humphrys gave him a calculator to count how many times he was interrupted.
- Labour director of communications Dave Hill spoke publicly of "the John Humphrys problem" after the presenter's robust confrontation with social security secretary Harriet Harman about plans to reduce payments to single mothers in 1997.
- An early morning three-minute interview with correspondent Andrew Gilligan in 2003 led to a confrontation between the BBC and the government. Gilligan said he had been told by a reliable source that a government dossier about the threat from Iraqi leader Saddam Hussein's weapons of mass destruction had been deliberately "sexed up". This ultimately led to the suicide of the source, Dr David Kelly, and the resignations of Gilligan, the BBC director general and the BBC chairman.
- Humphrys hastened the downfall of another director general, George Entwistle, in 2012 with a interview about how Newsnight wrongly implicated a former Conservative deputy chairman in a child abuse scandal. Entwistle, who struggled badly and appeared out of his depth, resigned soon afterwards.
- Humphrys got into hot water for a leaked off-air exchange about the BBC's gender pay gap with North America editor Jon Sopel in 2018. It followed the resignation of Carrie Gracie as BBC China editor over pay inequality. In what Humphrys described as a "jokey" exchange, he asked Sopel about "how much of your salary you are prepared to hand over to Carrie Gracie to keep her".