This is the UK Governments official notification website. In days of old important announcements such as awards would be printed in a paper, The Gazette, in order to become public record. In fact in the military your promotion would be "Gazetted" and the date of publication was the day you wore your new badges of rank.
Now online it is the place to go for reference and official public records.
About this site
The Gazette - the UK's official public record since 1665