The former England Under-21 striker Marvin Sordell has described football as “a beautiful game with an ugly persona” after citing his mental wellbeing as a big factor behind his decision to retire aged 28.

Sordell has announced his retirement after terminating his contract with the League One side Burton Albion, and is keen to help others who may be experiencing mental health issues. He had been with Burton since January 2017, havingjoined Bolton for a fee in the region of £3m in 2012 and represented Team GB at the London Olympics later that summer.

Sordell said he has lived his dream as a professional footballer but experienced an “ugly side to the game”, including racism and bullying.

“The six-year-old me would never even have dreamed of what the 28-year-old me has achieved in this game,” Sordell wrote on Twitter. “I managed to experience some of the greatest highs on offer: playing for England, for Team GB in the Olympics and in the biggest league in the world, the Premier League.

“In over 300 matches, for the nine clubs and three national teams I played for, I scored goals that I dreamed about as a young boy in the park.

“I’ll be honest though, the ugly side of the game that many of us are exposed to, has had a hugely detrimental effect on my mental health. I witnessed, and was on the receiving end of racism on several occasions and have seen an incredible amount of bullying, manipulation and verbal abuse to an extent which for many leaves a dirt stain on this industry.

“The combination of these aspects allow me to move on from being a professional football player, knowing that I will be a happier man, and also be able to love the game again, in a way that I haven’t for many years.”

Sordell has also had spells at Burnley, Colchester and Coventry since leaving Bolton and spent the second half of last season on loan at Northampton.

Last year he spoke candidly to The Guardian’s Donald McRae about how mental health had affected his career. “My mental health has been severely impacted throughout my career, therefore I feel it’s the right time to move forward in my life,” Sordell told the Burton website. “I have always been eager to help people who have had similar problems in their lives and going forward I’d like to be able to make a difference in football when it comes to mental wellbeing.”

Burton’s manager, Nigel Clough, said: “We want to thank Marvin for the contribution he has made during his time at Burton Albion. We totally understand his decision and he leaves with the very best wishes of everyone at the club. We are sure Marvin has a massive amount to contribute in helping people with their mental wellbeing and we look forward to seeing all that he achieves in the future.”