Chairman Paul Brenchley said Wisbech Town boss Brett Whaley has left the club at “such a pivotal time in the season”.
Whaley has opted to take over at Spalding United, who sit six places and 14 points above Wisbech in the Northern Premier League Division One Midlands.
In a club statement, Mr Brenchley said: “We are obviously disappointed to lose Brett at such a pivotal time in the season but that’s what happens in football sometimes.
“However, his departure must not distract us from the main focus of improving our league position, starting with the visit of Soham Town Rangers on Monday.”
Whaley ends his time at Fountain Fresh Park after joining Wisbech for a second time in February 2020.
Speaking to Spalding’s club website, he said the opportunity to join “was too good to turn down.
"I am aware how ambitious the club is and look forward to helping them achieve their goals."
Whaley added: “I would like to thank everyone at Wisbech Town for all their help and support over the last two years and wish them all the very best for the future."
Chris Lenton, who was assistant to Whaley at Wisbech and March, will take interim charge alongside coach Arran Duke at home to Soham on December 27, 3pm.
Wisbech Town FC said today (Friday) that "a formal application process for a permanent manager will begin in the New Year."
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