XL staff in Crawley contemplate their future
There will be "some significant redundancies" at holiday group XL, the firm's chief administrator has warned.
Alastair Beveridge of accountancy group Kroll said the decision was "regrettable" but unavoidable given that XL had run out of resources.
XL chairman Phil Wyatt added that the company's entire 1,700 UK workforce could be at risk.
While Kroll has ceased operations at XL's main UK business, its French and German units are continuing to trade.
Although XL's UK operations have been closed down, it remains possible that in the longer term a potential buyer or buyers could come forward for all or part of the business.
"We are thinking about a rescue plan for the survival of parts of the business," said Kroll partner Stuart Mackellar.
"Liquidation is well down the line."
XL staff have already been informed that they are likely to lose their jobs.
The 100 staff at a call centre in Swansea run by XL subsidiary Travel City Direct have been told to go home and expect redundancy letters in the post.
XL air steward Spencer Davis said the likely job losses were "just the way that the airline industry is going at the moment".
"We are now going to be competing for the same jobs with many other staff who have also been put out of work.
"There are a lot of people who woke up this morning without work, but we will have to just try and stay upbeat," he said.
The Unite union, which represents some XL staff, has complained about some employees first finding out about the job cuts through the media.
"Airlines that are struggling in the present climate are treating their workforce and the trade unions representing them with contempt," said Unite national officer, Brian Boyd.
"As recently as this week, representatives from Unite were discussing a wage claim with XL.
"Given the difficulties that aviation workers are facing today to hide the plight of the business from its employees is a disgrace."