DANGER looms as a slab of rock the size of a bungalow is set to fall from a popular climbing site in the Lake District.

Castle Rock, near Threlkeld, is one minor earth tremor away from a 1,500 tonne collapse, according to geologists.

The weakness in the slab is caused by the natural movement of tectonic plates over time, but it has shifted by 3.5cm in three years which is more than scientists would expect.

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The Fell and Rock Climbing Club and United Utilities, who manage the land, have erected signs warning climbers of the danger and urging them to avoid the area.

Despite it being inevitable that the rock will fall it is impossible to predict exactly when.

Dr Yani Najman, a geologist at the University of Lancaster, said: "It's moving but whether it falls tomorrow or at a later date I can't say. The size of the boulder is bigger than average - it is pretty huge."

There are two explanations for the rock's movement - freeze thaw weathering is when water gets into the cracks and freezes, expanding and widening the crack, tree roots can also force a gap to open up in the rock and both of these are evident on Castle Rock.

The popular climbing route is so fragile that a minor earth tremor could cause a dramatic collapse.
Dr Najman said: "We're not in Nepal so we are not going to get a major earthquake but there are small tremors and depending on the state of equilibrium of the rock that could be the final straw."