“I understand that ITV has decided the current situation can’t go on, and I want to do what I can to protect the show that I love.
“So I have agreed to step down from This Morning with immediate effect, in the hope that the show can move forward to a bright future.”
Schofield and Willoughby have long described themselves as “best friends” off-camera and have been on holiday together numerous times.
However, the pair have been beset by rumours of unhappiness in recent weeks, with critics pointing to his “awkward” demeanour on air, including tears and exaggerated jollity.
Reports have speculated that Willoughby was upset that Schofield did not tell her sooner about the situation with his brother.
They also speculated that their relationship never fully recovered from the strain of being vilified for allegedly jumping the queue at the lying in state of Queen Elizabeth II.
Last week, The Telegraph reported insiders as saying that Willougby has become exasperated by Schofield’s neediness since he revealed he was gay in 2020 and split up with his wife.
Bosses were also allegedly horrified by Schofield’s decision earlier this month to issue a statement responding to rumours of a rift, taking it as a sign of increasingly erratic behaviour.
The veteran presenter was said to have pushed hard for Willoughby to join him as regular This Morning co-host after Fern Britton stood down in 2009. Willoughby has previously acknowledged that she owes her career to him.
Their apparently genuine chemistry - they once turned up to work having partied all night together after winning a National Television Award - has been a sustained hit with audiences.
As well as co-hosting This Morning, the pair also fronted Dancing On Ice.
Willoughby said in an Instagram post: “It’s been over 13 great years presenting This Morning with Phil and I want to take this opportunity to thank him for all of his knowledge, his experience and his humour. The sofa won’t feel the same without him.”
Schofield graduated from presenting on CBBC’s Broom Cupboard to enjoy one of the most enduring careers in television.
The 61-year-old, who made his name alongside sidekick Gordon The Gopher on the BBC children’s television show, came to be seen as the king of daytime television.
Schofield was given the plum job on This Morning in 2002 after John Leslie was sacked.
Kevin Lygo, ITV’s managing director, media and entertainment, said: “Phillip is hands down one of the best broadcasters of his generation and we thank him for his two decades worth of absolutely terrific television on the This Morning sofa.