Tomnadashan Copper Mine

Overview

Tomnadashan, on the southern shore of Loch Tay in Perthshire, was a short-lived 19th-century copper venture developed by the Marquess of Breadalbane — remembered today less for its mining history than as the filming location for the Cave of Caerbannog in Monty Python and the Holy Grail.

History

The mine was developed between 1840 and 1860 under the direction of John Campbell, 5th Earl and later 2nd Marquess of Breadalbane, who sought to extract copper, sulphur and trace amounts of gold. Exploration began in 1842 under the Welsh miner Griffith Roberts, and by 1846 the workings employed 16 men and two boys; the venture ultimately produced only around 71 tonnes of saleable copper and sulphur ore, and closed in 1862 following financial losses after the Earl's death.

What remains

The mine's best-known feature today is a cave used as the filming location for the Cave of Caerbannog — home to the killer rabbit — in the 1975 film Monty Python and the Holy Grail.

Abandoned workings can be dangerous — unstable ground, uncapped shafts, flooding and bad air are common even where a site looks safe from the surface. This entry describes history and general location only; it is not an access guide.

Recorded claims

Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.

• Exploration at Tomnadashan began in 1842 under the Welsh miner Griffith Roberts, and by 1846 the workings employed 16 men and two boys; the venture ultimately produced only around 71 tonnes of saleable copper and sulphur ore before closing in 1862 following financial losses after the Earl of Breadalbane's death. ¹
• A cave at Tomnadashan was used as the filming location for the Cave of Caerbannog in the 1975 film Monty Python and the Holy Grail. ¹

Images

Sources

1. (secondary) Tomnadashan — Wikipedia

Record created: 20 August 2026 · Last researched: 20 August 2026