An appeal is being lodged over the government's decision not to upgrade Sir Arthur Conan Doyle's former Surrey home to Grade I-listed status.
Undershaw has been empty since a hotel operation ended in 2004
The Victorian Society said the Sherlock Holmes author's national standing had been wrongly appraised.
It wants Grade II-listed Undershaw to be upgraded, saying its "historical importance is indisputable".
The Department for Culture, Media and Sport (DCMS) said a request could be made for the decision to be reviewed.
The Victorian Society originally asked for an upgrade last July, at a time when Undershaw's present owner was planning to convert the building into four separate dwellings.
The planning application for the alteration was rejected by Waverley Borough Council in December.
But the society is still pushing for Grade I-listed status as it would open funding avenues for repair and refurbishment work.
The author and his family lived at Undershaw between 1897 and 1906
The rejection letter sent from the DCMS to The Victorian Society said: "The building lacks the level of special architectural interest which would justify a Grade I listing... [and] the integrity of the original design has been compromised."
But the society's senior architectural adviser, Dr Kathryn Ferry, said she objected to questions over whether Conan Doyle's standing "in the nation's consciousness" was great enough to justify an upgrade on that basis alone.
Dr Ferry said: "Conan Doyle and Sherlock Holmes are world-famous figures and people around the world care deeply about the house that played such a part in their existences."