It was also announced yesterday that Sir Dick Evans, the British Aerospace chief executive, is to join the board as a non-executive director, in a move seen as a victory for institutions keen to reduce Sir Desmond's boardroom power.
The row at the AGM came after Sir Desmond refused to tell shareholders why the United Utilities board had ousted chief executive, Brian Staples, on Monday after it passed a vote of no-confidence in him.
To a round of applause from the floor, one shareholder told Sir Desmond: "This is the second chief executive officer that we have lost under your chairmanship and I do not think, therefore, you should remain as chairman of the company if you will not justify your actions."
Mr Staples, one of the so-called "fat cats" of the utilities sector, left abruptly on Monday amid suggestions of boardroom concern over his private life. The company has denied that Mr Staples' decision to leave his wife and move in with the Sir Desmond's former secretary was a factor in his departure.
Mr Staples is line for a pay-off of around pounds 600,000. His predecessor Bob Thian, who left three years ago, departed with pounds 670,000 in compensation.
Asked later if he had ever considered resigning, Sir Desmond said: "Quite simply, no. Certainly not when I played a major part in taking it [the company] from pounds 1.2bn to almost a pounds 4bn company and a major multi-utility."
He claimed he and Mr Staples had parted on good terms: "There is no personal animosity and there never has been any. He left the company on Monday and we shook hands. It's like losing a friend. It's a sad moment. But life goes on. None of us is indispensable."
Sir Desmond rejected claims that institutions had put pressure on him to stand down to a non-executive role. "There were calls for a change in my role at the AGM a year ago. Subsequent to that we have met all our institutional shareholders. They understand our roles and we've not heard anything from them on this issue."
Sir Desmond also attacked the windfall tax. He said it would trigger a "comprehensive review" of discretionary revenue and capital expenditure, customer rebates and voluntary compensation schemes. United shares closed up 2.5p at 733.5p.