How Brassey's published wartime naval information

How could Brassey's publish detailed naval information during the Second World War without revealing classified material?

The annual was carefully vetted, and its independent appearance made it a useful channel for information Britain was willing to place in public.

A viewer asks how the annual could publish information that appeared sensitive during an ongoing war. Brassey's was permitted to do so after careful vetting. Its status as an independent publication could also make selected British claims more credible than a direct government announcement. The annual therefore combined open-source reference work with censorship and wartime information policy. Readers should value its contemporary detail while remembering that publication itself reflected official security decisions.