Former England defender Sol Campbell announced his retirement from football on Wednesday.
Best known as a centre-back with north London rivals Tottenham Hotspur and Arsenal, Campbell also played for Portsmouth and, more recently, Newcastle.
But the 37-year-Campbel was released by Newcastle at the end of last season and has not been able to secure a new deal with another club, partly as a result of injury.
He told Sky Sports News: "It was a very hard decision. It's hard to let go when you have been a top sportsman for a long, long time.
"To say that I am not going to play professional football again is difficult because I've had a long time at the top and I've put in a lot of work and it's taken a lot of dedication.
"I had a couple of offers to carry on -- one from a Premier League team, and another from a team who have just been promoted to the Premier League, but I had a foot injury and by the time I'd recovered from that people had already moved on," he added.
Campbell started his career at Tottenham but a controversial move to Arsenal in 2001 led to him being labelled "Judas" by sections of the Spurs' faithful.
He went on to have five successful seasons with the Gunners and was a member of Arsenal's 'Invincibles' team in 2003/04, while helping Arsene Wenger's side win three Premier League titles and two FA Cups.
He also scored Arsenal's only goal in their 2006 Champions League final defeat by Barcelona.
After leaving Arsenal, Campbell joined Portsmouth, where he won the FA Cup in 2008.
He returned to the Gunners for a brief second spell two years ago and also played for fourth tier club side Notts County before joining Newcastle, where he made just eight appearances in the 2010/11 season.
At international level, Campbell won 73 caps for England and appeared in six successive major tournaments for his country.