New Watford boss Rob Edwards had a clause in his Forest Green Rovers contract that effectively makes him a free agent as he prepares to take over at Vicarage Road.
Edwards is close to be appointing Roy Hodgson's replacement at Watford for next season - but the highly-rated coach's pending arrival has infuriated Forest Green.
In a strongly worded statement, a Forest Green Rovers spokesman said: 'FGR confirms the departure of Head Coach Rob Edwards. Rob was a key part of the team that gained promotion to League One this season. We're disappointed that our support, loyalty and honesty towards Rob has been repaid in this way - with negotiations taking place behind our backs.