A NEW heating and ventilation system was installed at the Big Pit mining museum nearly two years ago without planning permission due to an error.

The work was carried out in the attraction’s canteen and kitchen areas which are housed in the historic grade-II star pithead baths and canteen building at the former working mine that is now a museum that attracts around 150,000 visitors a year.

Work to replace the heating and ventilation system, and install an air source heat pump, started in January 2024 and was completed by the end of July that year.

However it has now been discovered though National Museum Wales had applied for listed building consent no application for planning permission had been made.

Following discovery of the error National Museum Wales submitted an application for retrospective planning permission in October last year.

That was two years and 21 days after it had made the application for listed building consent which is required whenever work is planned within, or impacting, a building judged to be of national, historical or architectural importance.

Torfaen council’s heritage officer Ross Cannon acknowledged the work had been completed “some time ago” but told the planning department: “It recently came to light that no planning application was submitted for the work.”

But Mr Cannon said he was “confident” the setting of the listed building had been preserved and impact of any work on the external appearance considered by the listed building application and was also content “there has been no detrimental impact.”

Torfaen Borough Council planning officer Mia McAndrew, whose reports approved the planning application and the listed building consent, stated: “The works were completed in 2024, but it recently came to light that this listed building consent application was not determined.”