In 1940 Winston Churchill declared 'We shall fight them on the beaches', but as local historian Chris Weston explains, in a previous war it was more a case of fighting them over the beaches – and a Norfolk site played a key part.

Long before his defiant speeches help rally a country at risk from the Nazi menace, Winston Churchill had a key role in establishing another barrier to invaders – and one in which a Norfolk town had a vital role to play.

In recent decades, almost every former RAF base in Norfolk and Suffolk has closed, not just large airfields such as Coltishall, but also smaller sites once serving other purposes.

But almost 100 years ago there came another closure – that of Great Yarmouth's Royal Naval Air Station. It was part of a network founded in 1912 by Churchill, then First Lord of the Admiralty, to run alongside the new Royal Flying Corps.

As tensions grew over the perceived growing German menace, the Royal Naval Air Service network was established around the country.

In Yarmouth it was placed on the South Denes, an area outside the town's walls which had had a variety of uses over the centuries, from cattle grazing to public hangings, horse racing to a place for fishermen to dry their nets.

It was earmarked for its new role by the Admiralty, which had been searching for a year for suitable land where hydro-aeroplanes could be handled or launched.

The site gradually witnessed the arrival of concrete hard-standings, service buildings, hangars and slipways, as this would be one of several RNAS stations for coastline protection. Commissioned on April 13 1913, the Station officially opened two days later, with a resident workforce of two officers and 15-20 men. At that time, it was one of only eight airfields in Britain, ready-built to combat aerial threats.

South Denes would combat raids by airborne Zeppelins and also spot German surface raiders. But the station also played a major part in submarine detection and during the First World War, up to 30 planes were based there.

Support came from additional landing ground facilities at satellite bases in Norfolk at Bacton, Burgh Castle, Holt (Bayfield) and Sedgeford, plus Aldeburgh and Covehithe in Suffolk. The Admiralty had also planned to take over Hickling Broad and use it as a reserve flying boat base and contractors duly built a concrete slipway, but this was never completed. In the event, Hickling was only used during the war for two emergency landings, but a separate arrangement allowed seaplanes destined for Yarmouth to land on the calmer waters of the broad if the sea were too rough.

Unlike some RNAS stations, Yarmouth was equipped to act as both a land and a flying boat base. Initially, seaplanes were launched by trolleys, until two slipways of heavy sleepers pinned to beach-driven piles were built, one at each end and intentionally placed opposite aircraft sheds, to aid arriving and departing aircraft. The first South Denes arrival was a standard military biplane, which flew in from Hendon on May 31 1915.

An early seaplane was the 100hp Gnome, described as a 'floating machine'. Normally a two-seater for a pilot at the front and rear observer, a third person could also squeeze into the rear but in practice that rarely happened. Personnel not living on-site were called 'The Ship's Company' and were treated well, with free transport between their lodgings and the base. The public were forbidden to approach the site when aircraft movements were likely, but could visit the planes on Sunday afternoons if no 'emergency' was declared.

The station still grew rapidly, also taking on civilians by late 1913, responsible for the care, maintenance and repair of machinery, but also acting as chauffeurs, storekeepers or telephone operators. In 1914 came seven officers, two warrant officers, 29 ratings and three pensioners.

During the early evening of January 19 1915, Yarmouth became the victim of the first-ever aerial attack on the UK by a Zeppelin airship. Two townsfolk were killed, but the South Denes planes were not able to intercept because they could not match the airship's cruising height. Their first Zeppelin success was not until November 27 1916, when an invader was shot down over the sea near Lowestoft.

One locally-based officer was Flight Commander Bob Leckie, who made history by shooting down two of the airships in 1917 and 1918. One contained Peter Strasser, the famous Zeppelin commander. Flt Cmdr Leckie was also involved in badly damaging a German U-boat.

As the war entered its final months, the RNAS was absorbed into the new RAF. Most RNAS sites - including Burgh Castle, Sedgeford, Holt, Aldeburgh and Covehithe - had closed by September 1919, the Yarmouth base lasting until late 1920. It was then used for commercial flights until the 1930s.

After this, the area became the South Denes Camping and Caravan site. New buildings were constructed but one former station building remained, even beyond closure of the camp site in 1990.

But then came yet another new era, as any trace of what had gone before was finally hidden by thousands of tons of sand, stone and concrete forming the new Outer Harbour complex

In June 2009, Yarmouth's Royal Naval Air Station was recognised with the unveiling of a plaque in honour of the men who protected the nation from the Kaiser's air force and navy. This is outside 25 Regent Street, the RNAS regional headquarters from 1913 to 1920, which later served as the local EDP and Great Yarmouth Mercury offices for many years.