Relatives of an Oxford professor are upset that a charity has 'marginalised' his name in favour of the author CS Lewis at the nature reserve they helped to buy.

The 12 acres of land, which once belonged to the writer of the Narnia stories, was bought in 1969 by wildlife trust BBONT, now BBOWT, following a generous donation by Dora Stephen, who lived in Lewis Close, Risinghurst, next to the reserve.

The green space was first called the Henry Stephen Nature Reserve in memory of Prof Stephen, who died in 1965, as specified by his widow.

Then, in 1980, the reserve was rededicated the Henry Stephen/CS Lewis Nature Reserve after CS Lewis's stepson, Dougie Gresham, visited the site and pointed out the writer's connections with the location.

Now relatives of Prof Stephen are concerned that his memory is being sidelined by another renaming of the reserve, which places greater emphasis on CS Lewis.

BBOWT says the reserve is now called the CS Lewis (In Memory of Henry Stephen) Nature Reserve.

Although a sign at the reserve itself recognises the Stephens connection, searches on BBOWT's website list the reserve as the CS Lewis Reserve, with no mention of Prof Stephen.

The family only discovered the change after approaching the charity to add Dora's name to the dedication following her death last year.

Kathy Stephen, the professor's grand-daughter, who lives in Abingdon, said: "In 1969, Dora donated to what was then called BBONT.

"She intended this reserve as a permanent memorial to her late husband, but was also conscious of the historical importance of the CS Lewis connection, and asked that equal mention be made of the two men.

"The reserve was then known as "The Henry Stephen/ CS Lewis Reserve".

"Now it seems that my grandfather's name has been deleted from the title of the reserve.

"Without the gift, the hillside might never have been made open to the public, to those interested in the writer, let alone for the preservation of a small wildlife habitat.

"BBOWT are still morally bound to remember Dora's generous gift, to recognise historic facts as she did back in 1969 and to maintain the terms of the original gift.

"Many people may prefer to associate this land uniquely with C S Lewis, but BBOWT is a nature trust, not a literary society, and we want the title changed back."

BBOWT head Chris Williams said: "Since 2003, the reserve has been called the CS Lewis Reserve (In Memory of Henry Stephen) and we are talking to the family about adding Dora's name to the dedication.

"This has been a Wildlife Trust reserve since 1969 and ever since, it has been in memory to two eminent people associated with the site, those of CS Lewis and Henry Stephen.

"In 2003, the trust decided to simplify the naming of some reserves, including this one, to avoid confusion on behalf of the public.

"It is untrue to suggest that it has been made for marketing purposes."