National Trust said it was supporting the fire service with its response and warned that the risk of wildfire remains “exceptionally high” in the warm, dry weather.
“We recognise that this incident will be worrying for many people across the Isle of Wight,” a spokesperson said.
“Headon Warren is a much-loved and nationally important landscape.
“At this stage, however, it is too early to fully assess the impact of the fire on the site, its wildlife and habitats. Once it is safe to do so, our teams will begin assessing the area and understanding the extent of any damage.”
The fire service has asked the public to avoid the area and said it was expecting to remain at the scene for the next 24 to 72 hours.
