Andy Harrison is quitting as chief executive of easyJet after four turbulent years in the role, during which he was strongly criticised by the founder and biggest shareholder, Sir Stelios Haji-Ioannou, over the budget airline’s strategy.

EasyJet said today: "Andy Harrison, chief executive officer, has indicated his desire to leave the company in order to seek new challenges."

The company said that the board has agreed that Mr Harrison will stay in post until the end of next June to give it time to find a successor. easyJet said the whole board, apart from Sir Stelios, had supported Mr Harrison's growth strategy.

Sir Stelios, who is a non-executive director and, with his family, controls 38 per cent of the company, has since autumn last year repeatedly stated that he believed Mr Harrison was ordering too many planes when the carrier should be conserving cash and reining back on expansion at a time of low demand for air travel.

Recently Sir Colin Chandler, the chairman, and Jeff Carr, the finance director, and two other senior executives have quit.

At the time of Sir Colin's departure in April, he let it be known that he was "fed up" with the continuing row with the founder.

Last autumn Sir Stelios refused to sign off the accounts because of Mr Harrison's growth strategy.

The board also revealed today that in May this year, when Mr Carr quit, leaving the company without a finance director and still with no permanent chairman, it had amended the terms of Mr Harrison's contract to put in place a retention agreement "to ensure his presence as chief executive through to at least the first quarter of 2010".

Mr Harrison's original contract had required him to give only six months' notice. The board has now amended Mr Harrison's employment terms a second time to keep him on until the end of June so that he can help to identify a successor. It is understood that he will receive a pay-off, but the terms are not yet being revealed. He is entitled to up to a year's notice payment and pro rata bonus. Last year he received £856,000 including a bonus of £266,000.

EasyJet has 109 Airbus jets on order for delivery by 2012, which will result in a 50 per cent increase in its fleet size.

The management of easyJet in September partially backed down and said that it would pursue a more cautious growth strategy.

The airline, which placed the order seven years ago on particularly good terms, has insisted that it cannot cancel aircraft without facing stiff penalties.

However, it can defer 50 per cent of committed orders for up to two years if it gives 18 months' notice

Meanwhile, in a move that was planned earlier this year, Sir Michael Rake, non-executive deputy chairman, who joined the board in June, will become chairman, taking over from Sir David Michels, who stepped up to the role on an interim basis after Sir Colin Chandler quit.

Sir Michael is the chairman of BT and joined easyJet in June as deputy chairman and senior independent director. Sir David will become senior independent director once Sir Michael becomes chairman.

Commenting on his departure, Mr Harrison said: "EasyJet is a great company with a strong management team and I am sure under Mike's chairmanship, easyJet will continue to grow from strength to strength.

“I am looking forward to being part of the process of selecting my successor and am committed to ensuring a smooth transition. I have loved being a part of easyJet's success, but am now looking forward to moving on to a new challenge."

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