John Hartson has claimed he "ruined Rangers single-handedly" as he revisited the collapse of his move to Ibrox.
The former Celtic star insists he was later told by an insider that not tying up the transfer was the "worst mistake" in the club's history.
Hartson went on to enjoy a successful stint at Parkhead after failing a medical across the city.
The big Welshman scored eight times against Rangers over five years at Celtic.
Rangers are now favourites to sign Hartson 's countryman Aaron Ramsey on-loan from Juventus and the 46-year-old has revisited his own Ibrox transfer tale on social media.
Hartson wrote: "I totally ruined Rangers single handedly, insider told me it’s the worst mistake they have ever done..
"4 winning goals in derbies. 8 in total should have been ten !! Signed (Tore Andre) Flo instead for 12m we all know how well he did for them."
Earlier, Hartson's former Celtic team-mate and Record Sport columnist Chris Sutton took a dig of his own as speculation over Ramsey went into overdrive.
He wrote: "I remember when Rangers thought they’d signed John Hartson… what happened next?"
