Rio Ferdinand has retired from football after being released from QPR following their relegation from the Premier League.
Ferdinand, 36, suffered heartbreak after wife Rebecca died from cancer at age of 34 earlier this month.
- BT Sport Football (@btsportfootball) May 30, 2015
The defender said on BT Sport: "This season I really found out that it was time to hang the boots up and get back in the house and watch other people play the game.''
Former United and England teammate Paul Scholes said of Ferdinand: "He was a great player, without a doubt the best centre-half I ever played with.
Congratulations to @rioferdy5 on his great career. Best I played with and best pairings I've seen with Vida/JT. Covered me very well too!
- Gary Neville (@GNev2) May 30, 2015
"I would say for a time as well he was the best centre-half in the world. He was such a pleasure to play with and play in front of. To play in front of him, he made your job so easy.''
Ferdinand played 504 times in the Premier League for West Ham, Leeds, Manchester United and QPR and was once the record transfer for a defender when he moved to Old Trafford in 2002 for £29.1 million.
- David De Gea (@D_DeGea) May 30, 2015
Ferdinand hailed the "genius'' of Sir Alex Ferguson, under whom he won six Premier League titles at Manchester United, as the key factor in his career.
In a statement, Ferdinand said: "After 18 years as a professional footballer, I now feel it's the right time for me to retire from the game that I love.
"As a 12-year-old boy, kicking around a football on the Friary Estate in Peckham, I never dreamt that I would play for my boyhood club West Ham, captain Leeds United, win the Champions League with Manchester United, or re-join my first manager Harry Redknapp at Queens Park Rangers.
"I will always regard the 81 times that I played for England, with immense pride. These are all treasured memories that will last a lifetime.
"Starting a career, every young man needs mentors. I found mine in Dave Goodwin, the district manager at Blackheath, and Tony Carr, the youth team manager at West Ham. They installed in me personality traits that lasted throughout my career. I will always be grateful to them.
"I'd like to thank Chris Ramsey, Harry Redknapp, David O'Leary and David Moyes who managed me at various times in my career, all the backroom staff who looked after me over the years, and the players that I played with. I would also like to thank the team who managed me off the pitch, Jamie Moralee and everybody at New Era.
- Edwin van der Sar (@vdsar1970) May 30, 2015
"Winning trophies over my 13 years at Manchester United allowed me to achieve everything that I desired in football. From a young child to today, that was all I cared about.
"None of that would have been possible, without the genius of one man, Sir Alex Ferguson. His greatest accomplishment in my eyes will always be how he developed us as men, not just as footballers. He will in my opinion, always be the greatest manager in British football history.
"I'd also like to thank and pay tribute to my wife Rebecca and my family, including my mother and father, for their sacrifices, their encouragement and their advice throughout my career.
"And finally, I'd like to thank all the fans from all the clubs - for without them professional football would not exist. I will miss each and every one of you on my Saturday afternoons.''
- Musa Okwonga (@Okwonga) May 30, 2015
West Ham academy director Tony Carr worked with Ferdinand as a youngster at Upton Park, and says anyone who does not appreciate the defender's contribution to the the English game is "blinded."
Carr said: "I just remember him coming to the training ground, he was choosing which club he would sign for. He was a tall, skinny, skilful midfield player.
"He had attacking instincts but the one thing that did strike me was his enthusiasm for the game, he just loved to play and that shone all the way through for me. In some respects some of that is missing from the game these days with some players."
Information from the Press Association was used in this report.