Martin O'Neill has shocked Aston Villa by resigning as manager only five days before the start of the season. Kevin MacDonald, the reserve team manager, takes over as caretaker manager and will prepare the team for the opening Premier League game of the season against West Ham on Saturday.
Randy Lerner, the Villa owner, had maintained that O'Neill had committed his future to the club in May amid speculation that the Northern Irishman was leaving, but he has now decided to quit.
O'Neill said on the Villa website: "I have enjoyed my time at Aston Villa immensely. It's obviously a wrench to be leaving such a magnificent club. I would like to pay tribute to the Villa players, my coaching staff and the Villa supporters for all the support and encouragement they have given both the club and me personally during my time as manager.
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"I wish them all the best for the future. I will obviously be assisting the club in the immediate short term with regard to the handover of my duties."
Paul Faulkner, Villa's chief executive, said: "The club would like to thank Martin for the great work he has done at Aston Villa over the past four years. He has helped to establish the club in the upper echelons of the Premier League, has taken us to Wembley and we have also qualified for European competition for the past three seasons under his management. We wish him the best in the future."
Richard Bevan, chief executive of the League Managers Association, paid tribute to O'Neill: "The LMA shares Martin's disappointment at him leaving Aston Villa," he said. "He has achieved great success not just with Villa but throughout his managerial career. He is a great example to all aspiring managers having built the foundations in non-league football to then go on to successfully manage at the highest level in the game."
O'Neill has improved the fortunes of Villa since replacing David O'Leary during the summer of 2006, achieving three consecutive top-six placings in the league.
Lerner had backed O'Neill in the transfer market during that spell but it became clear this summer that the funds would not be available to help take Villa on to the next level. The team's challenge for a top-four place fell away after they lost to Manchester United in the Carling Cup final in February.
Lerner insisted that Villa would have to adopt a sell-to-buy policy and O'Neill was resigned to losing the services of the England midfielder James Milner to Manchester City. That followed on from the departure of Gareth Barry to Eastlands last year.