London's Great Ormond Street Hospital is locked in a legal battle with a Canadian author over the rights to Sir James M Barrie's classic novel, Peter Pan.

Author Emily Somma has filed suit in San Francisco claiming the characters in Peter Pan are no longer protected by a copyright awarded to the hospital in 1929.

Sir James was a governor at the hospital and left it the rights to his tale about the boy who never grew up as a bequest.

The hospital could lose out financially if Ms Sommers wins her case.

Hospital spokesman Stephen Cox told BBC News Online Great Ormond Street has declined Ms Sommer's offer of royalties from her book - After The Rain: A New Adventure For Peter Pan.

Copyright was awarded to the hospital in 1929

"We are taking sensible precautions to protect the hospital," he said.

"We don't want to spend money on lawyers.

"We would rather spend money on children, but copyright is as much property as a building and the money we receive is useful for buying research and equipment."

Great Ormond Street has already warned Ms Somma to halt publication of her book, which has been published in Canada and can be purchased through the internet.

Unnoticed

US copyright protection for Sir James' works would normally have expired in 1987, a half-century after the author's death.

In a letter ordering Ms Somma to halt publication of her book, the hospital's lawyer, Alvin Deutsch, contends that a 1976 US law extended the copyright protection for Peter Pan until the year 2023.

Her lawyer disputes that.

Ms Somma's After The Rain, in which Pan is brought home from Neverland to grow up, was published by Ontario-based Daisy Books.

The Canadian edition went largely unnoticed until Somma began to solicit publishers in England.

The hospital has authorised a series of films based on the original Peter Pan, including Walt Disney's 1953 animated Peter Pan and Hook, the Stephen Spielberg adaptation.

Great Ormond Street opened with just 10 beds in 1852 and now cares for more than 100,000 children every year.