The network was established in 1990 after a national conference held on the subject was covered in The Independent on Sunday and generated a huge amount of correspondence.
Its purpose is to offer self-help groups in which people who hear voices feel accepted and can share their experiences. It encourages people to accept and live with their voices in a way that gives them control and helps them regain power over their lives.
"We believe they are similar to dreams - symbols of our unconscious minds," explains the charity's website. "Many people begin to hear voices as a result of extreme stress or trauma."
HVN says the traditional treatment for voice-hearing is major tranquillisers, administered to reduce hallucinations. However, it is keen to stress the benefits of treatment by psychiatrists, who explore the meaning of the voices its members hear.
And for those who heed the call, World Hearing Voices Day this year will be on 14 September.