Shares in Thomas Cook have fallen 28% in early London trading.
It comes after the travel company issued a warning that profits would be hit by unrest in the Middle East and North Africa, and by weak UK spending.
Europe's second-largest travel firm said continuing political unrest had affected bookings to destinations such as Tunisia, Egypt and Morocco.
It also said the profitability of its UK business had been hit by the "squeeze" on consumer spending. More...