RAF Hell’s Mouth (Porth Neigwl)

RAF Hell’s Mouth (Porth Neigwl) was located near to the village of Llanengan, a couple of miles from Abersoch, near the western end of the Lleyn Peninsula in North Wales. The whole site is now privately owned farmland and there is little to suggest its former use to the casual observer.

General Details and History

RAF Hell’s Mouth was commissioned in February 1937 and was originally a Relief Landing Ground for RAF Penrhos, located about 5 miles to the north east. During July to October 1940 there were a number of Luftwaffe raids on Penrhos which in turn, led to the erection of three hangers at Hell’s Mouth and an upgrading of the airfield to an Emergency Landing Ground for Penrhos and the area generally. At some later date, a fourth hanger was built next to the other three.

Hell’s Mouth and Penrhos were used throughout WW2 for armarment training, air observer, bombing and gunnery schools. Associated with these activities were a number of different types of targets and ranges used in the training:

  • Offshore Bombing Targets – There were three of these, two for use with practice (smoke) bombs and a single live target located mid-way between the practice targets. The targets consisted of rafts about 20ft square, the practice targets being moored 1000 yards from the beach and the live target further away for safety reasons at 2000 yards from the beach. Practice smoke bombs aimed at the targets were sighted from three ‘Quadrants’ situated near the beach/cliff around the bay and the bearings telephoned through to Penrhos. Quadrant No.1 was located on the southern ‘corner’ of the bay alongside the No.1 Practice Target Signal (or Range Arrow, understood to be painted white). Quadrant No.2 was located near to the airfield, alongside a searchlight installation and the Live Bombing Signal (range arrow). Quadrant No.3 was situated on the north western end of the bay near to where the Rhiw to Mynytho road comes close to the cliff. Occasionally night bombing practice was carried out by illuminating the targets by the searchlight mentioned previously. The targets were maintained by boats from a Marine Section of RAF Penrhos based in Pwllheli harbour. The Marine Section also made sure that other shipping was kept away from Porth Neigwl when training was taking place. An Air Sea Rescue base was also located at Pwllheli.
  • Air Gunnery Towed Targets – Often older service aircraft were converted to target tugs to tow flag and drogue targets which were shot at by trainee air gunners from training aircraft such as the Avro Anson. Each student used bullets with a different colour dye or paint and when the targets were released by the tug aircraft over the airfield at Hell’s Mouth, instructors could easily assess the trainees success by the different traces of colour around the bullet holes. It is thought that the target tug aircraft flew a course parallel to the coastline of Porth Neigwl, roughly in line with the offshore bombing targets. The training aircraft would then fire their guns towards the towed targets so that they were firing out to sea.
  • Air to Ground Gunnery Targets – A line of 10 ‘Frame’ air-to-ground targets was situated to the north of the airfield a short distance from, and parallel to, the line of the cliff. The targets were either rail-mounted or located adjacent to a straight length of ‘Decauville’ style track, two foot gauge and approximately 700 yards long. Three buildings were associated with these targets, a single Main Markers Shelter located to the landward side of the railway track and at its centre, and also two Wing Markers Shelters at the ends of the railway track. There were 5 ‘Frame’ targets either side of the Main Markers Shelter. It is not clear what the ‘Frame’ targets looked like.
  • Moving Target Range – this was completed in July 1940 and is of similar design to others in the UK built around the same time. For further details about this type of gunnery range, please see the 200 Yard Moving Target Ranges section of the website.

As can be imagined from the list above, this now tranquil corner of North Wales was quite a dangerous place to be during the late 1930’s and early 40’s.

The largest aircraft to land at Hell’s Mouth is understood to be a Vickers Wellington. The aircraft landed safely following an emergency and when the time came to leave, just managed to take-off again from the small airfield.

Hell’s Mouth remained operational for a short period after WW2 but by the Spring of 1947 range clearance had begun so that the land could be returned to agricultural use.

Site Visits 2003 and 2006

There are a number of buildings and concrete bases still extant on the site though there is an ever present risk that these may be demolished at some point in the future. Visible remains include:

  • The base of one of the original four ‘Bellman’ hangers
  • A number of ‘Stanton’ air raid shelters
  • A substantial brick built machine gun post or pillbox
  • The Main Markers Shelter and one of the Wing Markers Shelter buildings relating to the air-to-ground gunnery range (referenced as R1 & R2)
  • Walls and concrete bases of the 200 yard moving target range – used for air gunnery training
  • The base of Quadrant No.2 used for plotting ‘fall of shot’ for the three bombing targets moored out to sea
  • The remains of the Live Bombing Signal (range arrow) – to guide trainees towards the live bombing target 2000 yards offshore
  • Part of the perimeter track is now a public road between Towyn and Pentowyn

Photographs of some of the remains can be found on the following pages with additional descriptive notes. Also included on the pages are some questions to assist with research into RAF Hell’s Mouth.

If you have any further details on RAF Hell’s Mouth, I would welcome any information. Please email me at john@thegilbys.org.uk .


Data used in this website has been obtained from a number of sources including books, various websites, museums, personal interviews and site visits. Any errors contained herein are the responsibility of the author. Specific sources of information include:

  • “Wings Across the Border: a history of aviation in North Wales and the Northern Marches”, Derrick Pratt & Mike Grant, Bridge Books (Vol.2 2002, Vol.3 2006)
  • “Wings of War Over Gwynedd: Aviation in Gwynedd during World War II”, Roy Sloan, Gwasg Carreg Gwalch, 1991
  • “The Legend of Llandwrog: The story of an airfield and the birth of the RAF Mountain Rescue Service”, Edward Doylerush, Midland Counties Publications, 1994
  • “RAF Penrhos near Pwllheli, 1937-45, and RAF Llandwrog near Caernarvon, 1940-45”, David Annand, published by the author, Tywyn, 1986

Comments are closed.