An investigation by the paper into two mystery devices recently installed above bridges in Tavistock and Peter Tavy has revealed that they are monitoring debris levels in the river.

The devices sparked speculation among residents, with some suggesting the Environment Agency had installed them to monitor water levels, though the agency told the paper that it had not.

However, Devon County Council (DCC) has now confirmed that it has worked alongside the University of Exeter to install the cameras on Vigo Bridge in Tavistock and Harford Bridge in Peter Tavy as part of a project to protect historic bridges. The cameras will monitor debris accumulation in the river near the bridges and alert the council’s bridge teams when it reaches a critical level, especially during periods of heavy rain.

A DCC spokesperson said: “When debris collects around [them], it can increase pressure on the structure and raise the risk of flooding or damaging the structure. At the moment, this is monitored mainly through inspections, which can be difficult during storms or when river levels are high.

“The work will help us better protect historic and modern bridges, target maintenance resources more effectively, and improve safety during extreme weather. The findings could also help other councils manage similar risks on rivers across the country.”

The council has emphasised that the cameras are not being used for surveillance purposes and do not record people, vehicles or nearby properties. The solar-powered cameras are temporary and will be taken down once the project ends.

Vigo Bridge was built in 1773 and named after the Spanish naval port of Vigo, one of the locations visited by Sir Francis Drake. Harford Bridge is a Grade II-listed structure and likely dates from the 16th century, with evidence of some mid to late 19th-century rebuilding.