Bookends Bookshop in Westgate has been given permission to turn the top floor of its 16th century premises into an adults-only section.

But the move has been criticised by Gloucester Civic Trust.

The shop building is regarded as one of the finest examples of a timber-framed building in the country.

News of the internal changes could put a stop to the Trust's guided heritage tour of the building planned for 11 September.

Philip Moss from the Trust said: "I was walking around the shop in preparation for the tour.

"I was quite shocked as I didn't know they were converting the building.

"They were setting up display cases with certain items in them.

"The items in the shop were surprising for such a historic building."

Bookends manager Brian Thompson said: "We will be setting up an adult department in our bookshop.

"We'll be selling adult themed magazines, adult toys and 18 certificate videos.

"But we are being very, very respectful of the building.

"There's not going to be flashing lights and naked women - we are a bookshop at the end of the day.

"We've got permission to open to convert the shop. We aren't a licensed sex shop so we can't sell R-rated films.

" A spokeswoman for English Heritage said the building is "an exceptionally fine merchant's house, notable for the quality of its surviving detail which includes original surviving patterned leaded glass".

The house was used as judges' lodgings in the 19th century and was home to a former mayor of Gloucester.