Rob Edwards has been appointed as the new head coach of the Hornets.
Dale Vince, the chairman of Forest Green, accused the club's former CEO of faking his departure and entering advanced talks for the position at Vicarage Road.
The club confirmed that he had left his position with negotiations taking place behind their backs over a switch toWatford.
The appointment was confirmed in a statement, which said that he had a contractual provision allowing him to leave Forest Green Rovers at any time to discuss employment opportunities at other clubs.
The 39-year-old took over at Forest Green a year ago.
After a playing career that saw him play for three different teams, he moved into coaching. He was given his first-team debut in December 2002 by Graham Taylor.
After failing to save the club from the drop from the premier league, the Hornets will have a new manager at the end of the season.
The Hornets were demoted back to the Championship on Saturday after a 1-0 defeat at Crystal Palace.
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In his first season as head coach of the Hornets, he has only won two of his 15 games in charge.
The Hornets have not won at home in 11 games, with the former England boss unable to turn that around.
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Vince was less than impressed by the developments, as he had called Edwards on Tuesday evening as speculation mounted.
Vince exclusively told Sky Sports News that he knew it was real when he started speaking.
In football, people come and go all the time, so it was overwhelming for me. The manner of it is important.
I wish him well, but it is not good from Rob, who claims to be starting a new era. He has let us down, but he knows it, so we will move on.
Vince said that the negotiations could begin in the proper manner if they had been approached by Hornets initially.
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The kind of thing which gives football a bad name and the kind of thing which shouldn't happen is whatWatford advised Rob not to tell us specifically.
There will be some more formal, more proper process to end Rob's time here and for it to start atWatford.
The club will begin their own search to find a replacement for Edwards, who took over in the summer of 2021.
Vince said that they had a list of candidates and would just crack on with it. We just move on.
It is hard not to let it take the shine off what has happened, promotion and winning the title, but it will not affect what we do in the future.
I think everything will be fine, and if there is karma in football, we will meet Watford in the Championship in a few years time.