LONDON (AFP) - Britain was plunged into travel turmoil Friday as the country's third largest tour operator went bust at the same time as the Channel Tunnel remained closed due to a fire. Airports saw chaotic scenes after the XL Leisure Group called in the administrators, leaving tens of thousands of passengers stranded, while travellers booked for the tunnel scrambled to find alternative routes. At Gatwick airport south of London the two travel crunches combined, with thousands of people seeking to fly to France due to the tunnel closure, at the same time as XL customers were left grounded by the operator's woes. "We arrived at our check-in desk this morning and were just handed a letter telling us what had happened," said Julian Castle, who with his wife Marion had booked flights with XL for a two-week holiday in Florida. Administrators have been called in to see whether the company can be saved from total bankruptcy. Britain's Civil Aviation Authority (CAA) said the XL collapse was probably the biggest holiday operator failure for 20 years. The company had operated flights to more than 50 destinations in Europe, the United States and Africa. The CAA said it would bring back people already on holiday who had been left without return flights. Customers queuing at Gatwick - XL's main departure point for package holidays - had no idea of XL's collapse until they were informed by airport officials. Graham White, 27, an estate agent from London, said: "We didn't find out about it until we got here. I'm pretty annoyed." Meanwhile, there were similar frustrations at London's St Pancras station, the British terminus for trains travelling through the Channel Tunnel to France and Belgium. The fire erupted Thursday afternoon on a freight train about five kilometres (three miles) from the French end of the tunnel, forcing the evacuation of some 30 people, mostly truckers. While the blaze was rapidly brought under control, British and French firefighters battled all night to finally extinguish it. Many passengers were forced to spend an extra night in London or Paris Thursday as flights between the two cities quickly became fully booked, while ferries were also in heavy demand. To help matters, some bus services in London were facing disruption due to a strike by drivers and other staff over a pay row. Members of Unite union at firms run by the First transport group were on strike for 48 hours, affecting buses in the east and the west of the British capital.