Helen Shelby is a biologist who designed the Supreme Barrier Reef as a replacement for the Great Barrier Reef of the north-east coast of Australia, as the former became badly damaged during the 20th century.
When she and her son Robby Shelby came to examine the reef, they discovered that it had been bleached by acidic water. Unfortunately, this not only damaged their submarine but also their diving suits whilst they swam to an air pocket in the reef. Helen called Gordon Tracy for assistance, and he was more than willing to help them save the Supreme Barrier Reef, despite Lady Penelope reminding Gordon that International Rescue's job is to save people in danger, not the environment.
Helen has a no-nonsense attitude and doesn't like small talk, according to her son Robby. She appeared in Deep Water and was voiced by Jennifer Saunders.