Ihenacho sang on some of the group's biggest hits, including Dry Your Eyes, toured with The Streets and performed alongside Skinner at the Brit awards in 2006.
He is now attempting to launch a career as a solo star after joining British Tv talent show The Voice as a contestant, but his reappearance in the spotlight appears to have irritated Skinner, who took to his official blog to comment on Ihenacho's contribution to the group.
Skinner wrote, "Leo The Lion (Ihenacho) wasn't in the streets. He was a session singer on a few album tracks. He also sang on tour for a bit. He wasn't part of any songwriting."
The remarks have infuriated Ihenacho, who hit back in a series of posts on his Twitter.com page, writing, "You are a total disgrace...!! How f**king dare you... session singer..!!???... Egotistical a**e hole... Explain to the fans why we haven't spoken for years... You refuse to be happy for me... After all these years... You gonna post that..!!!!!... It's just incredible how some people can never ever want others to succeed..."