The 44-year-old is understood to have informed bandmates – Gary Barlow, Mark Owen and Howard Donald – that he wanted to quit the band last week.
Last night, he released a statement in a bid to explain his decision to shocked fans.
“I want to start by saying how proud I am of what we have achieved together over the years.
“However, at a band meeting last week I confirmed to Mark, Gary and Howard that I do not wish to commit to recording and promoting a new album.
“I have spent some of the best years of my life with Take that and I’d like to thank everyone who has been a part of my journey, including my bandmates, who I feel are like brothers to me.
“Most especially my gratitude goes to all of the good and kind, beautiful and ever-loyal fans of the band, without who none of this could have been possible.”
Jason said there were no disagreements with the band – and he thought about leaving shortly after Take That’s Progress tour ended in 2011.
“There have been no fallings out, only a decision on my part that I no longer wish to do this.
“I know how much Mark, Gary and Howard enjoy writing and making music, and they know that they have my full support and encouragement to continue on with what is to be another chapter for the band.”
It’s thought Take that will continue with Gary, Howard and Mark. Robbie Williams, who left Take That in 1995 but performing with them on their last tour, is not believed to be rejoining them on a permanent basis.
Gary, Howard and Mark reacted to Jason’s news as a “sad day for us”.
“Jason’s energy and belief in what this band could achieve has made it what it is today, and we’ll forever be grateful for his enthusiasm, dedication and inspiration over the years.”