Martin Allen has left Barnet for the fourth time to take over National League side Eastleigh.
The 51-year-old first managed the Bees between 2003 and 2004 before leaving to take over at Brentford.
He returned in 2011 but left weeks later to manage Notts County before returning to the club a year later.
A stint in charge of Gillingham followed before he took over from Edgar Davids with Barnet struggling in the Conference.
His first full season led to Barnet winning the Conference title for a record third time and he has guided the Bees to a mid table position so far this season.
Barnet Chairman Tony Kleanthous said: “Martin has asked to be released from his contract so he can join Eastleigh.
“The approach came out of the blue yesterday but it was quite clear that Martin had decided that he wanted to take the opportunity they were offering to him.
“He leaves with our best wishes having done a great job helping to rebuild the football club after our relegation into the National League.
“Our promotion two years ago was one of my highlights as Chairman and I was always aware Martin would be in demand as a result.
“The club is undergoing many changes. We have made the transition off the field needed for us to progress through the Football League and we must ensure our on-field development matches the facilities we have created.
“Martin’s departure presents us with an opportunity and we intend to appoint somebody who will help develop our younger players and integrate them into our first-team, as well as bringing in players who can play at a higher standard.”
In the interim development team coach Rossi Eames will take charge of the first-team affairs, assisted by academy manager Henry Newman.