Colchester have sacked manager John Ward following their winless start to the League One season.
Joe Dunne has been appointed as caretaker manager ahead of this weekend's clash at home to Hartlepool.
Chairman Robbie Cowling said in a statement: "In so many areas, John Ward will leave Colchester United in a better position than when he first took over as first-team manager.
"So much of Colchester United is better than it has ever been, but sadly that is not being reflected in first-team results and the board has decided that this action is required to stop the negativity of the on-field results impacting on the other areas of the club that have also been drastically improved.
"I would like to thank John Ward for his time in charge. He has done more for Colchester United than many people realise, and the board of Colchester United and especially myself would like to wish him all of the very best for the future.
"Joe Dunne has agreed to take over in the short term and I am sure that everyone will give Joe their full support."