The journalist, whose funny asides in between stories have often gone viral, making him a household name, confirmed the news online on Thursday.
Sam Taylor, head of live and breaking for BBC News said McCoy had been a “sharp, funny and a great colleague”.
GB News described the incoming anchor “one of Britain’s best-loved and most charismatic journalists”.
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“It has been a delight to have Simon at the helm of the BBC News Channel and BBC News at One,” Mr Taylor continued.
“We’ll miss his one-liners, pregnant pauses and commitment to breaking news in every form, and wish him the very best for the future.”
One of McCoy’s new GB news bosses Andrew Neil, tweeted: “Welcome aboard Simon. Great that you are joining [us].”
In the New Year, McCoy told BBC viewers there would be package of the “highlights of 2020”, only for nothing appear on screen. “Exactly, it’s farewell 2020,” he quipped, referring to the pandemic.
On another occasion he began his news report holding a pack of A4 printer paper in his hands, instead of the usual iPad.
McCoy also made viewers laugh when he irreverently reported on The Queen’s garden parties being cancelled. “A quick line of breaking news that may affect you, but it doesn’t affect me,” he said.
Wait. Is Simon McCoy leaving? https://t.co/9jr5xFgYDJ
— Scott Bryan (@scottygb) March 25, 2021
He got a fit of the on-air giggles while reporting on a man playing the piano to monkeys.
While reading a script full of dog puns about the Scottish Parliament Dog of the Year contest, he asked one camera to film the autocue to show the audience “what I have to deal with.”
When new Prime Minister Boris Johnson told an interviewer he painted model buses in his spare time for fun, McCoy – referencing an infamous Brexit NHS funding pledge – retorted: “I wonder what he writes on the side of it?”
McCoy drily revealed that the Duke and Duchess of Cambridge were due to have a baby – which turned out to be Princess Charlotte – in April 2015, by saying: “Now, bearing in mind they announced that she was pregnant back in September and it was thought she was around two or three months pregnant, I’m not sure how much news this is. Anyway it’s April, so clear your diaries, get the time booked off – that’s what I’m doing”.