Colchester English Study Centre was opened in 1969 by the publisher Oxford University Press as a school of English for Specific Purposes. Since then, it has gained an international reputation for excellence in all the English language courses that it organises. The school is well-known for the high standards of service offered to its students and partner agencies throughout the world. It remains the only all-year English language school in Colchester, and all of its courses are accredited by the British Council. It is an official centre for the University of Cambridge ESOL examinations and for the IELTS examination.

In 1988 the school opened its partner organisation International Language Holidays, which provides summer junior courses in the region. These are also accredited by the British Council.

Previous clients of CESC include:

3M - AEG Telfunken - British Airways - BP - French Chamber of Commerce - French Ministry of Education - Deutsche Bank - Esso - Fiat - Fuji Oil Company - German Foreign Ministry - Gulf Air - Hessisches Landesbank - Hoechst - Iberia - IBM - Kuwait Oil Company - Libyan Ministry of Oil - Lufthansa - Mobil Oil - Norwegian Medical Association - Petromin, Saudi Arabia - Pakistan Int Airlines - Racal - Shell - Siemens - Sony - Volkswagen - Volvo