England test captain Andrew Strauss has retired from all forms of cricket with immediate effect.
Strauss, 35, said during a press conference at Lord's that his decision was motivated by a drop in his batting form.
He denied it was related to the furore over Kevin Pietersen, who was axed from the side weeks ago after sending text messages to the South African team.
The decision comes after an illustrious career which saw him guide England to home and away Ashes wins and the coveted number one spot in the world rankings.
"I haven't batted well for a long time now. I knew with my own energy levels and motivation that I wasn't going to improve, batting-wise ... It's a hugely sad moment in many ways," he said.
He added: "I am extremely proud of everything I have achieved as a cricketer and I have found myself very fortunate to play in an era when some of English cricket's greatest moments have occurred. I have loved every minute of it," he said.
"It hasn't been something that occurred overnight. It has built over a few months. I would like to go out on my own terms with my head held high and I think this is the right time."
Alastair Cook, already England's one-day captain and Strauss's opening partner in the five-day game, was announced as the new skipper of the test team.
Strauss insisted the Pietersen "incident" did not contribute to his decision, which he said had been made before the saga erupted earlier this summer.
The episode strained the team after Pietersen admitted sending controversial texts, criticising Strauss and coach Andy Flower, to South African cricketers.
But Strauss said: "I first spoke to Andy (Flower) about it prior to the Kevin Pietersen incident rearing its head, it just hasn't been a consideration at all."
"It was one of those decisions you know in your heart," he added.
Former England captain Mike Atherton said Strauss' departure may make it more difficult for Pietersen to return to the England team.
He told Sky News: "There will be a perception out there, although it may be a false one, that Pietersen has had something to do with his decision to retire and that may harden some of the players' views against him."
His move follows England's loss of its status as the world's number one test team after a home series loss to South Africa this month.
Cook told reporters that he will meet the challenge of taking England back to the top of the rankings "head on", adding he had "huge boots to fill".
"He has been a fantastic captain, has led from the front for three-and-a-half years and is a true ambassador for the game," Cook said.
The 27-year-old's first challenge as captain will be the four-match series in India in November.
Former England captain Michael Vaughan tweeted, "Strauss...Three Ashes wins...Two as captain...21 test 100's...Debut at Lord's...50th as captain at Lord's...Can't believe Straussy didn't cry...lol."
ECB chief executive David Collier said Strauss "has shown tremendous integrity, dedication and commitment both on and off the field.
"His legacy within the game will be felt for many years to come and we now need to continue to build on the progress we have made under his leadership."