Houllier has ended his ninth-month reign with immediate effect after suffering heart problems which meant he could not take charge of the team for the final five games of the season. He showed his faith in Bent by splashing out an initial £18million to Sunderland in January and he responded with nine goals in 16 games. Bent said: "It is sad for me to see Gerard go. He signed me, invested a lot of money in me. "He showed a lot of faith in me. "But your health comes first and, if he's not well enough to come back, then he needs to take a break." It has been common knowledge for 24 hours that Houllier's reign was coming to an end after he underwent further medical tests before the weekend. Villa will now step up their search to find a replacement with Fulham's Mark Hughes one of the early names to be linked with the post. Doctors have advised that Houllier will require further time to recuperate although the 63-year-old is not ruling out an eventual return to the game. Villa chief executive Paul Faulkner said: "We regret the circumstances of Gerard's departure and, naturally, we wish him well in his continued recovery. "I know I speak for everyone associated with Aston Villa in expressing our hope that Gerard will return to full health as quickly as possible and we wish him all the best for the future." Faulkner added: "As a board we are very conscious of the need to ensure that the club is prepared fully to meet the demands of the new season. "To that end, we have already embarked upon the process which will lead to the appointment of a new manager." Houllier replaced Martin O'Neill in September and found it difficult to win over the Villa fans who called for him to be sacked after home defeats by Sunderland and Wolves. But there were signs that Villa were turning the corner during the second half of the campaign and they climbed to ninth in the Barclays Premier League. Houllier said: "I am extremely disappointed that I will not have the opportunity to manage Aston Villa next season. "My health has improved considerably since I was taken ill on April 20. I now intend to take the next few months to concentrate on recuperating fully before I may return to football. "I was very much looking forward to the prospect of my first full season as Villa manager and returning for pre-season training to prepare for the campaign ahead, a luxury that I did not have last season. "I have been extremely touched by all of the messages I have received and by the reaction of people throughout the world of football. "It has been an honour to manage this great club and I wish everyone connected with Aston Villa every success for the future." Villa have yet to make any announcement over the future of Houllier's assistant, Gary McAllister, who took charge of the club in his absence.