On Wednesday, the night before Barnsley Council adopted the Hoyland South masterplan - the third masterplan laying out future business and housing land in the town - members of Extinction Rebellion used a solar and battery-powered projector to cast messages onto the stone.
Ci Davis, from the group, said: “The masterplan is a wholly irresponsible scheme, and the full council meeting looked for support for that destruction despite the local community asking them to stop and review.
“Councillors are supposed to represent people, not toe the party line but they don’t have to follow the cabinet, and they shouldn’t if what’s happening is wrong.
“We’re asking them to stop projects adding more greenhouse gases into the atmosphere and causing further damage to biodiversity.
“We totally support jobs, but not those that are just a race to the bottom.
“With the projector, we were able to non-violently carry messages in a form that might otherwise be known as graffiti, but which only lasts as long as the pixels stay on the building.
“It also directed people to the town hall, where these decisions are being made.”
A council spokesperson said: “We recognise that people have the right to express their opinions and would ask this is done in the correct way.
“It is disappointing that some people have chosen to use the Town Hall to project these messages to make their point.
“Although we understand the right for groups and individuals to voice their opinions, we do not condone messages using unacceptable language being displayed on public buildings, or anywhere else across the borough.
The council will take measures to protect our public buildings in the future.
“This has been one of the most consulted developments in recent years.
“We understand people have different opinions, but we have made clear throughout, both the reasons and significant challenge we face in needing to develop some parts of the borough to drive forward jobs and investment.
“With the Government forecasting 2.6 million unemployment figures and possibly a third of Barnsley’s businesses forecasting redundancies, it is important we make use of key employment sites for our residents and their families.”