Andrew Strauss today described his decision to step down as England Test captain as being in the "best interest" of the national team.
Strauss confirmed his retirement from all forms of the game at a lunchtime press conference at Lord's.
The 35-year-old's decision brings down the curtain on a 100-Test career that peaked with an Ashes victory in Australia 18 months ago.
But since then Strauss' form has dipped and after his side relinquished their place at the top of the Test rankings after the recent 2-0 series defeat against South Africa he believes the time was right to leave the game.
"After much thought over the last few weeks, I have decided to step down as England Test captain and announce my retirement from all forms of cricket," he said.
"It has clearly been a tough decision to make but I believe that it is both in the best interests of the England cricket team and myself to step down at this stage.
"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."
The England and Wales Cricket Board confirmed that Strauss would be replaced by Alastair Cook, who flanked his opening partner at today's press conference.
Cook paid tribute to his former skipper and admitted he would be a tough act to follow ahead of his first Test series in charge in India later this year.
"Andrew's contribution to England cricket in recent years is evident to everyone who follows the sport but only those of us who have been lucky enough to share a dressing room with him are fully aware of his immense contribution to our success," Cook said.
"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.
"To have played 100 Tests for your country is a phenomenal achievement and I want to congratulate him on a superb career. I know this can't have been an easy decision for him and everyone in the dressing room will be sad to see him go.
"I'm very excited by this new challenge, it is a huge honour to be appointed Test captain and am very much looking forward to captaining the side in India this winter and beyond but my immediate focus is on this current NatWest one day series.
"Once the series is over I will turn my attention to the Test captaincy and building on the work Andrew has started."
England won 24 of those 50 Tests under Strauss, making him the national team's third most experienced leader and the second most successful behind Michael Vaughan.
The Middlesex batsman also led the side to home and away Ashes triumphs as well as their surge to world number one last summer, the first time England had held the position since the rankings were introduced.
That position was, however, lost following a summer of unrest highlighted by Kevin Pietersen's axing from the England set-up.
Pietersen admitted to, and apologised, for sending text messages to members of the South African team before he was left out of the third Test at Lord's earlier this month.
Strauss was reportedly at the centre of some of the "derogatory" messages and was due to meet the South African-born batsman for clear-the-air talks.
Strauss denied the controversy had prompted his decision.
"No, not in anyway, I've been speaking about it for a while. 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.
"I first spoke to Andy about this a few weeks ago and said I'm considering it and would talk to him at end of the (South Africa) series, by the time I spoke to him again my mind was made up and I think he knew that."
He added: "It's a very tough decision. For me the driver to it all quite frankly was my form with the bat. In truth I haven't battled well enough for a long time now.
"I think for a captain to perform his role properly, it's important you're not a passenger in the side, but also that people aren't speculating as to whether you should be in the side or not. I think that would have been too big a distraction to the side going forward.
"It's a hugely sad moment in many ways."
Manager Director of England Cricket, Hugh Morris, said that he would meet with Pietersen and team director Andy Flower in the coming weeks.
Flower has called on Pietersen to divulge the contents of the texts as the first major step towards welcoming him back into the squad.
"What we will be doing is myself and Andy Flower will meet with Kevin and we will be doing that in due course," he said.
"We are where we are and we will be seeking those discussions and they will be behind closed doors."
Morris was more forthcoming in his tributes for Strauss who, after taking over as Test skipper from Pietersen following his public rift with former coach Peter Moores in 2009, steered England to one of their most prosperous periods.
"He has been a great servant for Middlesex County Cricket Club and England and an outstanding ambassador for the game, not just in England but across the world," he said.
"Andrew's influence and impact on England cricket should be measured in much more that runs and catches. In partnership with England team director Andy Flower he has brought remarkable leadership and direction to the England team and has presided over one of the most successful periods in our cricket history.
"He will always be remembered for leading England to back-to-back Ashes victories and to the top of the ICC world Test rankings.
"I would like to thank Andrew for his enormous contribution to the England cricket team and for cricket in England and Wales."
Cook took over as one-day captain from Strauss following last year's World Cup and now faces the task of galvanising both the 50-over and Test teams ahead of an arduous 18 months.
Following this winter's tour of India, back-to-back Ashes series will loom large on the horizon before the World Cup in Australia.
"Obviously I've got huge boots to fill," Cook said.
"Andrew played 100 Test matches, 7,000 runs, and it feels like I've spent all my England career walking out to bat with him.
"That's a huge hole to fill - and unfortunately it might mean I have to take the first ball now.
"As an England dressing room it's going to be hard to fill his boots, and I think that's a huge compliment to Andrew Strauss.
"We've got India away and we've got two Ashes series in the next 18 months, so there's a lot of cricket to play and hopefully I can do a good job.
"I think Straussy summed it up, you've got to throw yourself into it and meet the challenge head-on and I hope I've got the leadership qualities to be able to do that."
ECB chief executive David Collier said: "On behalf of the ECB and everyone involved in cricket I'd like to thank Andrew Strauss for his outstanding contribution to the game.
"Andrew has been a highly successful captain and opening batsman for Middlesex and England who will be remembered for leading the side to two Ashes victories and to the top of the test rankings. He has shown tremendous integrity, dedication and commitment both on and off the field and under his leadership the side has grown immeasurably and reached new levels of professionalism.
"Andrew's calmness and authority when dealing with some of the most difficult moments in our sport in recent times should be applauded and I have no doubt that his contribution as an ambassador for the game will be recognised by anyone who has had an opportunity to spend time with him. 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.
"I would like to congratulate Alastair on becoming Test captain. He has shown he has the traits needed to be a successful captain and has demonstrated his leadership capabilities as one day captain over the last 16 months. On behalf of the ECB I would like to wish Alastair and Andy Flower all the very best for the exciting challenges that lie ahead."
Regarding his future plans, Strauss admits he would love to be involved in cricket in some capacity in the future.
Asked about his next step, he said: "That's always a difficult question to answer, I've got some ideas, some things I'd like to get involved in.
"I think long-term I'd like to have some more challenges ahead of me in whatever it is I do, but I'm going to take a bit of time to think about what exactly that means and what that might be.
"And while I'm taking that time I'm looking forward to spending some time with my family and probably getting my golf handicap down a bit as well.
"I would love to stay involved in the game, I'm hugely passionate about the game, I feel like I've got more to offer the game at some stage in the future but in what capacity I've got no idea."
STRAUSS' RECORD AS CAPTAIN
Highest score: 169 (v West Indies, Feb 2009)