Gannon, who became the Coca-Cola Championship club`s third boss this season in February following the sacking of Mark Cooper, had been offered a long-term deal to remain at London Road. However, the 41-year-old dropped a strong hint following Tuesday night's 4-0 defeat at fellow strugglers Scunthorpe that he would not be taking up the offer due to family reasons and that has been confirmed.
In a statement on the club`s official website, theposh.com, Gannon said: "Having given the matter considerable thought I have decided not to accept the football club`s offer of a contract to be the manager for the coming seasons."
He added: "I have enjoyed myself immensely over the last few months and I would like to thanks the chairman Darragh MacAnthony and Barry Fry for the privilege of working in the Championship with Posh.
"I am not driven buy personal or financial gain or a mechanical professional drive. I have become a devoted family man over the last few years and the separation from my family over the last season has created a big void in my personal happiness and contentment.
"Given that my partner is now pregnant and expecting our second baby in July, the need for their stability, security and happiness becomes increasingly important to me."
Gannon added: "I still have an important job to do for the remainder of the season in showing that the players and the club are much more capable than what has been previously shown, and that we are determined to use this period to prepare successfully for the new season.
"There is valuable work to be done over the coming months to ensure the successful return to the Championship.
"I would like to thank the fans for the wonderful support I have received during my time here and I hope I can give them plenty to look forward to for the future."
Source: PA
Source: PA