British travel firm Thomas Cook said Chief Executive Manny Fontenla-Novoa would step down with immediate effect, following a spate of profit warnings and a steep drop in the company’s share price since the start of the year.Fontenla-Novoa was criticised by analysts and investors after the group issued a profit warning in July, its third in 12 months.The value of Thomas Cook shares has dropped by two-thirds since January, but Fontenla-Novoa told Reuters last month his own position was not under pressure. Sam Weihagen, deputy to the chief executive, will take on the role of interim CEO, the 170-year-old firm said on Wednesday, adding that the process to identify a permanent successor was already underway.Shares in Europe’s second-biggest travel company rose more than 7 per cent to 64.95 pence on Wednesday following Fontenla-Novoa’s departure. Rival TUI Travel’s shares were down 1.9 per cent at 180.7 pence.Separately, Thomas Cook said underlying operating profit for the third quarter fell 22 per cent to 20.1 million pounds ($32.76 million), as tough conditions in Britain and unrest in the Middle East and North Africa (MENA) hit trading.Peel Hunt analyst Nick Batram said although the company’s trading position was no worse than the recent profit warning, the “report will not encourage many buyers”, despite Fontenla-Novoa’s departure.Thomas Cook said the MENA impact for the quarter was estimated at 25 million pounds and expects a similar disruptive effect in the fourth quarter.The company also confirmed full-year profit would be lower than it previously expected at 320 million pounds.