A major incident has been declared as firefighters battle a large heathland fire on the Suffolk coast about 3 miles from the Sizewell B nuclear power plant.

Suffolk fire and rescue service was called to reports of a wildfire at Dunwich Heath, near Leiston, shortly after 5.30pm on Wednesday, and crews remained at the scene on Thursday. About 90 firefighters were tackling the blaze, and several people had been evacuated. Firefighters have said there is not thought to be any danger to Sizewell B at this time, and an EDF spokesperson said the wildfire was not affecting operations at the power station.

The energy supplier said it was “closely monitoring the situation” and it is understood Sizewell B has an emergency plan in place that covers a range of scenarios including a fire on site.

The fire service said a major incident had been declared “due to the size and complexity” of the blaze. People have been urged to avoid the area where possible and keep windows and doors closed.

In an update on Thursday morning, the service said: “At this time there is no current risk to Sizewell B, due to the distance from the fire and the direction it is travelling (easterly). However, this is a live and dynamic situation and as a result any further updates will be shared accordingly.”

Crews have been focused on protecting nearby properties, while preparations have been made for the potential evacuation of about 200 caravans at the Cliff House holiday park if conditions deteriorate.

Dan Davis, a station manager with Suffolk fire and rescue service, said: “Crews from Leiston attended the scene and were met with what is a large-scale, wind-driven forestry fire.

“The incident has subsequently been upgraded to a major incident. We currently have approximately 90 firefighters on scene working incredibly hard in arduous conditions to bring this fire under control.”

Specialist drones were used overnight to assess the fire’s behaviour and help operational decision-making, while crews deployed multipurpose all-wheel-drive Unimogs and 4×4 quad bikes.

In Scotland, crews said they were making significant progress tackling a wildfire in the Cairngorms that broke out two weeks ago.