When in 1999 the Supersonic Airbus A-900 airliner started getting into airline service a lot of airlines put their Concordes on the market and switched to the more economic A-900. This meant that the Concordes were relatively cheap.
The EasyJet company bought 12 of them in a bid to open a low fare connection between London and New York. EasyJet operated the Concordes for 5 years but the operating cost of the aircraft proved too high to make the venture profitable. In 2005 the last EasyJet Concorde flight was made.