The building has been left empty for more than a decade
Squatters have started to make minor repairs to a historic building in Derby that they have occupied for months.
The former Smiths Clockworks in Queen Street is said to have been the meeting place for scientist Erasmus Darwin and inventor Benjamin Franklin.
The squatters said their aim was to bring the state of the derelict building to the public's attention.
Its current owner Joseph De Winter, who lives in London, said he did not want to comment on the issue.
The building has been empty for more than a decade and was purchased for £347,000 in 2001.
The squatters have made minor repairs to part of the roof. The clockworks was founded by John Smith in 1856.
John Cadwallader, chief executive of Derby CityScape, said the building should be brought to the attention of English Heritage.
The protesters have a good objective but many building projects were being shelved now because of the economic situation and the state of the property market, he said.
The original planning permission for the property, which has now expired, included refurbishment of the building.
"The squatters have done a great job in bringing the history of the building to everyone's attention but the next step is to talk to English Heritage," he added.
Squatter Martin said there had been "a load of important historic events that have happened here" including clockmaker John Smith and Sons taking over the site and Erasmus Darwin and Benjamin Franklin using the building for meetings.
He said: "Everybody involved has been amazed at the history of the building because no-one really knew much about it."
He added: "We hope to work with the owner and not against him, but so far we have not heard anything from him."