Here COI is the Central Office of Information: a British government body that used to produce books, films, posters, and reports explaining what government departments were doing. It was a peacetime information office — the people who made official explanations for the public, not a secret service. It does not exist any more; the British government closed it in 2011 and moved the work elsewhere. You will meet the name in older documents, history books, and film credits. It is a UK institution, so it is not part of everyday English in Taiwan. Though actually, in business and university English today, COI much more often means something else entirely: conflict of interest. This entry is only the old British office.