Fred, a lifelong United supporter, lost £500,000 in 1998 when he was the first bookie ever to pay out early on the Premier League title winners.
United were 12 points clear of Arsenal when he paid out to his delighted punters but the invincible Gunners bounced back to pip the Reds.
Fred Done said: "Even with the Derby to come a five point lead is just too much for City, so once again I’m letting my United punters have their dough early to the tune of just over half million quid.
“Back in 1998 Fergie told me to never pay out early again but Sir Alex need not worry, I’ve not got it wrong this time, United are past the post for a record twentieth Premier League title.”
Fred said that despite writing off City for this season, he thinks the Blues will win it next season - he has installed them as 7/4 favourites for next season’s Premier League.