"It had so many repercussions and shook me up so much," the presenter told The Mirror.
"If it was a decision I had to make now I probably wouldn't do it. I went from being a great broadcaster, or at least a very acceptably good one, to being a somewhat inadequate one overnight."
Lynam made the move five years ago after signing a four-year £26,000-per-week deal to host ITV's football coverage. He then decided to leave ITV in 2004 and is currently presenting Countdown as a replacement for Richard Whiteley.