Martin Newland resigned today as editor of the Daily Telegraph.
Mr Newland, 44, will leave at the end of the month and staff were officially told of his departure this morning.
It follows the recent appointment of John Bryant as editor-in-chief of the Telegraph Group.
A Telegraph source said: "Martin felt that he could not continue in his position since the appointment of John Bryant as editor-in-chief."
Mr Newland said editing the Daily Telegraph had been "a privilege".
He said: "It has been a marvellous experience working with so many great journalists and building the newspaper's reputation as the UK's market leader."
He thanked Sir David and Sir Frederick Barclay and Aidan Barclay for their "kindness and good wishes".
Telegraph Group chief executive Murdoch MacLennan said: "Martin Newland has guided the Daily Telegraph with distinction through a difficult period, especially during the sale of the company by Lord Black.
"He has attracted a team of brilliant writers, pioneered the new business and sports sections and overseen the re-design and modernisation of the newspaper.
"Both our proprietors and I had hoped to work with him for the foreseeable future so it is with regret to us all that he has decided to move on.
"I would very much like to thank Martin for his considerable contribution to the Telegraph and we wish him every success in whatever he decides to do next."Reuse content