Ex-Sheffield United, Burnley and Rotherham United defender joins League One rivals of Sheffield Wednesday and Barnsley

The 43-year-old from Maidstone started his playing career with Chelsea and had a handful of loan spells at Sheffield United between 2002 and 2004 before joining the club permanently in the summer of 2004.

He left the club for Burnley a year later and spent three years at Turf Moor before signing for Watford and then Notts County. He was loaned to Rotherham United for a short spell at the end of 2012 before joining Portsmouth.

Harley, who has left his role with the development side at Chelsea to join John Mousinho’s backroom team, has now returned to Portsmouth as an assistant. Pompey are 10th in the table, 12 points adrift of Barnsley in sixth.

Portsmouth’s sporting director Richard Hughes said: “We spoke to quite a few people and both John and I were really impressed with Jon. His face would light up whenever he talked about Pompey and you can tell he has an affinity for this football club.

"Coupled with his coaching background – where he’s spent 10 years with Chelsea and worked with some of the best talents in the country – he’s going to add value. We feel that he can provide excellent support for John and so we’re delighted to have him here. He’ll be a great asset for the club.”

Head coach Mousinho added: “Jon had a fantastic playing career and competed at the top, while he’s had 10 years working with Chelsea at the highest level of development football.

“He was the outstanding candidate during the recruitment process and knowing him from my time on the Pro Licence, he’s a great guy who’s going to fit in with what we’re trying to do here.

“Jon is an excellent coach and Chelsea have a great track record of bringing through players to feature in their first team or have good careers elsewhere – he’s had a big role in that. That was a big part in coming here because we also want to bring young players in here and help to develop them.”