Norwich have sacked manager Bryan Gunn after only two matches of the season, including an opening-day 7-1 defeat.
The 45-year-old was appointed caretaker boss in January after the departure of Glenn Roeder, before being named permanent manager in May.
After being relegated last season, City began life in League One with their heaviest ever home defeat as calamitous defending saw Colchester run riot.
Assistant manager Ian Butterworth has been put in temporary charge.
The board said efforts were already being made to appoint a long-term successor as manager.
Fans react as Norwich fire Gunn
Norwich's dismal opening-day defeat saw two fans run on to the pitch and appear to throw their season tickets at Gunn.
The Canaries followed up Saturday's disastrous start by winning 4-0 at Yeovil in the Carling Cup on Tuesday, with Grant Holt - one of 12 summer acquisitions - scoring a hat-trick.
However, that victory was only Gunn's sixth in 21 matches in charge, with 10 defeats recorded during his tenure.
Canaries' chief executive David McNally told the club's website: "Bryan has worked tirelessly for this football club for more than two decades, not least since taking over team affairs in January.
"However, the board met this week following Saturday's unacceptable record home defeat in our opening game of the season.
"The board, after lengthy consideration, unanimously felt a change was in the best interests of all parties concerned, in order to give us the best possible chance of achieving our objectives.
"Our goal this season remains unchanged. We want to be promoted and the next manager will have that as his number one priority."
Gunn spent almost 12 years at Norwich as a player, between 1986 and 1998, making 477 appearances.
Butterworth, a former team-mate of Gunn's at Carrow Road, made 235 appearances for the club between 1984 and 1994.
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