Nant Ffrancon Pass

The Nant Ffrancon Pass in Snowdonia, North Wales, is the long steady climb of the A5 road between Bethesda, Gwynedd, and Llyn Ogwen in Conwy. The summit at 312 metres (1,024 ft) is at Pont Wern-gof, about one-third of a mile beyond the eastern end of Llyn Ogwen. From here the road descends through Nant y Benglog to Capel Curig and through to Betws-y-Coed. The A5 is the Holyhead to London trunk road, which was re-engineered by Thomas Telford between 1810 and 1826. The original road through the Nant Ffrancon was constructed by Lord Penrhyn in the late 18th century, and at Capel Curig in 1801 he built a coaching inn, which is now Plas y Brenin, the UK National Mountaineering Centre.

Nant Ffrancon itself is a steep-sided glacial valley dropping to Bethesda between the Glyderau and the Carneddau. The valley starts in Cwm Idwal, carrying water from Llyn-y-Cwn through the Devil’s Kitchen and Llyn Idwal to join the Ogwen Valley below the Ogwen Falls on Afon Ogwen. Unlike Lord Penrhyn’s road, which largely followed the valley floor, Telford carved much of his road out of the north-eastern slopes of the Nant Ffrancon, thereby encountering difficulties in construction and future maintenance. But this enabled Telford to observe a maximum grade of 1 in 14 along the whole route from London to Holyhead in order to facilitate the operation of horse drawn mail coaches throughout.

It has been frequently used as a filming location for British film-makers, including doubling for the Khyber Pass in the Carry On film Carry On up the Khyber, and doubling for the Himalayas in the Doctor Who serial The Abominable Snowmen. The Pass was also used as a location in the 1950s film Inn Of The Sixth Happiness.