Twitter's co-founder and CEO, Jack Dorsey, has announced his departure from the company. CTO Parag Agrawal will replace him, while Bret Taylor will take over as the new chairman of the board.

Dorsey has led Twitter as CEO since 2015 - after being pushed out of the role in 2008. Despite leaving Twitter, he will continue to be the CEO of Square. In a statement, Dorsey said he decided to leave Twitter because he believes the company is "ready to move on from its founders".

Dorsey added: "My trust in Parag as Twitter’s CEO is deep. His work over the past 10 years has been transformational".

In a letter to employees, Dorsey revealed he will finish serving his term on the board of directors until "May-ish". Dorsey said he believes it’s critical a company can "stand on its own, free of its founder’s influence or direction". He also said the decision to leave was his own, and a tough one.

He described himself as both really sad and yet really happy. "I love this service and company... and all of you so much", Dorsey said.

Agrawal released his own note to employees ahead of an all-hands meeting, where he said he joined Twitter 10 years ago.

"I’ve walked in your shoes, I’ve seen the ups and downs, the challenges and obstacles, the wins and the mistakes", the incoming CEO said. "But then and now, above all else, I see Twitter’s incredible impact, our continued progress, and the exciting opportunities ahead of us".