From Longman Dictionary of Contemporary Englishtake it as read (that)take it as read (that)especially British English to feel certain that something is true although no one has told you it is true SYN assume You can take it as read that we will support the project. → read
Examples from the Corpus
take it as read (that)• Let us take it as read that Hawkwind started quite a few trends in their time. 