Dounreay, near Thurso on the north Caithness coast, was established 70 years ago as an experimental nuclear power site.

In 1962, the fast reactor inside the dome was the first in the world to provide electricity to a national grid.

Enough power was generated for a small town.

The reactor was shut down in 1977.

There was a plan to possibly keep the golf ball as a landmark to recall the local area’s role in the development of nuclear power, but the idea was later scrapped.

It was decided to stop repainting the entire structure every 10 years due to cost.

The site’s operator at the time, DSRL, said the steel was deemed thick enough to last as a protection until the reactor inside was dismantled.