Tributes have poured in for veteran BBC broadcaster Sir Terry Wogan who has died aged 77, after a short illness.
BBC director general Tony Hall hailed him as "a broadcasting legend".
Sir Terry hosted a long-running TV chat show, fronted the Eurovision Song Contest and was the face of Children in Need, while his Radio 2 breakfast show regularly had around 8m listeners.
Broadcaster Simon Mayo said: "There was no-one better at being a friend behind the microphone than Sir Terry".
Sir Terry, who had not been seen in public since November when he pulled out of hosting the annual Children in Need telethon, died "after a short but brave battle with cancer", his family said.
He leaves his wife Helen and their three children. The couple also had a daughter who died in infancy.
"He passed away surrounded by his family. While we understand he will be missed by many, the family ask that their privacy is respected at this time," his family said, in a statement on Sunday.
Born in Limerick in the Irish Republic, Sir Terry's career spanned 50 years on both radio and TV, and even included a brief stint in the charts with his 1978 cover of The Floral Dance.
He also provided the UK commentary for the annual Eurovision Song Contest for some 28 years, with many viewing his acerbic comments on the show as the highlight of the event.
From 1972 to 1984 he presented the breakfast show on Radio 2 as The Terry Wogan Show, returning after a decade away in 1993 to front the re-branded Wake Up To Wogan.
The second incarnation of the show regularly drew more than 8m listeners - dubbed TOGs, or "Terry's Old Geezers and Gals".
Radio 2 controller, Bob Shennan, said he was "one of the greatest and most popular radio hosts this country has ever heard".
He added: "We were brightened by his wonderful personality and charm as he woke us up every weekday morning, becoming an essential and much loved part of our lives.
"His millions of listeners adored him, as did his whole Radio 2 family. We will miss him enormously"
"Just the most warm-hearted, generous, funny, clever, life-affirming man," tweeted Radio 2 colleague Dermot O'Leary. "Part of the foundations of BBC Radio 2 - so very sad."
"He was probably the greatest broadcaster since the invention of the microphone," said another Radio 2 colleague, Jeremy Vine.
"He lived for the red light and the sense that there was a listener at the end of the microphone. He only ever spoke to one person, because the greatest radio is intimate
A gift for sounding natural
By David Sillito, media and arts correspondent
There's a wonderful archive recording of the day President Kennedy visited Ireland in 1963.
The man capturing the scene for RTE - of people pushing past the police cordon - is a young Terry Wogan.
His accent is a little stronger, but he is definitely the Terry Wogan that was still broadcasting 50 years later.
The man you met off camera was very much the man you heard on air and it was obviously a gift - a gift for sounding natural, real.
Fellow Radio 2 presenter Paul O'Grady says there was no falsehood about him and that captures it perfectly - people can sniff out inauthenticity in a second and whether you liked him or not, there was nothing phony about him.
However, what made that extraordinary is that he could access that wit and apposite comment again and again, year after year, in front of huge audiences on Children in Need and the Eurovision Song Contest.
Live broadcasting is terrifying - things are always going wrong and a poorly chosen word or a comment that misses the mark can haunt you for years.
Yet with Sir Terry, I can't think of one. It's a clever man who can make that look easy.
Director general Lord Hall said: "Terry truly was a national treasure. Today we've lost a wonderful friend.
"He was a lovely, lovely man and our thoughts are with his wife and family. For 50 years Sir Terry graced our screens and airwaves. His warmth, wit and geniality meant that for millions he was a part of the family."
Sir Terry began his career on Ireland's national broadcaster RTE as a newsreader and announcer, moving into light entertainment before joining the BBC, where he would stay for the rest of his career.
Radio 2 presenter Simon Mayo described him as a "radio genius", saying: "The staple of all great radio is the friend behind the microphone - and he was the ultimate friend behind the microphone."
"He could speak in a way that had you smiling... had you laughing, and touched you to the heart," said veteran DJ Paul Gambaccini. "The audience knew he was with them - and he was part of their lives."
Simon Mayo's thoughts were echoed by another Radio 2 colleague, Ken Bruce, who called Sir Terry "part of the fabric of our lives"
"He could have done anything in broadcasting, whatever he wanted to do. What he chose to do was bring his vast wit and intelligence to entertainment."
DJ Tony Blackburn said: "He was part of our lives, a real radio legend. He loved what he was doing and he gave an enormous amount of pleasure."
Graham Norton, who took over from Sir Terry as Eurovision commentator in 2008, recalled his influence: "He made it seem effortless and, for a young boy in Ireland, he made it seem possible. RIP Sir Terry Wogan. I'll raise a glass during song 9."
Many alluded to his natural charm and ebullient wit, as well as his loathing of rehearsals and preference for broadcasting "off the cuff".
President of the Irish Republic Michael D Higgins said Sir Terry was "always proud of his origins in Limerick", and returned frequently to his native country.
"His rise to the top of radio listenership in the United Kingdom was a great tribute to his breadth of knowledge and in particular his unique, very personal sense of humour."
Fellow countryman Dara O'Briain tweeted: "Hard to quantify what he achieved, not just in broadcasting but for the Irish in Britain" adding that he "opened to the door to all who followed".
Prime Minister David Cameron paid his own tribute, saying: "His charm and wit always made me smile. Britain has lost a huge talent."
And Sir Elton John paid tribute to Sir Terry on his Instagram account.
The singer posted a picture of the two of them together, writing: "Such a special and funny man.
"A brilliant broadcaster and presenter. He came to our civil partnership celebration and was a loyal supporter. Love to his family. E xxxx."
Sir Terry anchored the Children in Need TV appeal from when it was first broadcast in 1980, continuing to host it after retiring from regular broadcasting.
Chairwoman Stevie Spring said: "Most people know him as the face of Children in Need, but he's the heart of the charity and has been for 35 years."
"He didn't take or demand the credit for what he achieved at Children in Need. His legacy lives on... in all of the millions of disadvantaged children whose lives he has changed."
Sir Terry met a huge array of personalities, including superstars such as Tina Turner and Elton John, as host of the chatshow Wogan from 1982 to 1983 - with Kylie Minogue one of those remembering him as "a true gent".
Ant & Dec, Chris Moyles, Clare Balding all left tributes on Twitter, as did music stars such as Elaine Paige, Cat Stevens and Ronan Keating, who called him "king of the airwaves".
Sir Terry announced his retirement from Wake Up to Wogan in September 2009, making his final regular appearance three months later.
When he broadcast at breakfast for the final time in 2009 he told listeners: "The years together with you have not only been a pleasure but a privilege. You have allowed me to share your lives with you.
"When you tell me how important I have been in your lives it's very moving. You have been every bit as important in mine."
Sir Terry, who continued to front a live Sunday morning show, last appeared on air on Radio 2 on 8 November 2015.
Chris Evans, who took over the station's breakfast show, wrote on Twitter, on Sunday: "We are all so terribly sad upon hearing of the passing of Terry. I can't put into words how the whole Radio 2 family is feeling."
Director of BBC Radio, Helen Boaden said: "He always had the best interests of the listener at heart".
"Radio in this country without Terry Wogan - it feels like a very big gap," she said.
The One Show: A Tribute to Sir Terry will be broadcast at 19:00 GMT on Monday 1 February.
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