It was announced today at the firm website that they have entered Compulsory Liquidation and are now under the control of the Official Receiver.
The UK Civil Aviation Authority (CAA) said the tour operator had "ceased trading with immediate effect".
A support service is being provided by The Civil Aviation Authority to assist customers currently overseas and those in the UK with future bookings .
The United Kingdom authorities will charterer 45 jets to bring the travellers home and they will fly 64 routes today.
The current size of the fleet will make it temporarily the United Kingdom's fifth largest airline.
Operators including EasyJet and Virgin have supplied some aircraft, with jets coming from as far afield as Malaysia.
If you are travelling and will be affected by the announcement that Thomas Cook has collapsed, you should visit thomascook.caa.co.uk for the latest updates on the situation.