The shooting down of the Zeppelin L70 over Norfolk during the last air raid of the first world war was today commemorated with a blue plaque.

Eastern Daily Press: Unveiling of a new blue plaque commemorating an Zeppelin L21 shot down by in 1916 by Lt Egbert Cadbury. Picture: James BassUnveiling of a new blue plaque commemorating an Zeppelin L21 shot down by in 1916 by Lt Egbert Cadbury. Picture: James Bass (Image: Archant Norfolk � 2013)

On August 5, 1918, Major Egbert Cadbury, heir to the chocolate empire, and his air gunner Capt Robert Leckie took off from Great Yarmouth's South Denes air base, pitting their flimsy biplane against the airship menace.

Five giant German Zeppelins were intercepted by British biplanes and the L70 – one of the latest Zeppelins, whose crew included the head of the German airship service, Peter Strasser – was attacked by Maj Cadbury's plane at 17,000ft and plummeted in flames into the sea off Wells.

Cadbury and Leckie were both awarded Distinguished Flying Crosses, Cadbury sealing his reputation as the station's most celebrated 'Zepp killer.'

Maj Cadbury's proud descendants, grandson Justin Cadbury and his great grandson Leander Cadbury, attended the ceremony to fix the plaque at his Kimberly Terrace lodgings, now part of the Carlton Hotel, and remember the historic episode.

Andrew Fakes, of Great Yarmouth Local History and Archaeological Society which has put up more than 56 plaques around the town, said the attack 'was the culmination of the air war over Britain in the first world war when it was demonstrated that airships were vulnerable to powered aircraft.'

Egbert Cadbury was a member of the long-established chocolate maker and Quaker family who as a Cambridge undergraduate joined the Navy in 1914 as an Able Seaman but quickly transferred to the Royal Naval Air Service and was posted to Yarmouth.

He worked alongside mechanic Henry Allingham who witnessed Great Britain's first air raid in Yarmouth in 1915. An icon for remembrance, he died aged 113.

Cadbury married the daughter of flamboyant Gorleston vicar Rev Forbes Phillips. Mary Phillips was an accomplished singer and was giving a charity concert in a Yarmouth theatre when the order to scramble came through. Maj Cadbury, who was also singing, left immediately and drove to the airfield taking off in a De Havilland F4 aircraft.

A photograph of Maj Cadbury is displayed in the Time and Tide Museum, in Great Yarmouth, alongside an aluminium cigarette box which the flying ace had made out of Zeppelin parts.

During the early war years, planes struggled to combat the airships and pilots even contemplated such desperate measures as ramming them.

But by the end of the war they were armed with incendiary ammunition which was used in the final attack. Maj Cadbury had downed Zeppelin L21 off Lowestoft in 1916 and witnessed the top gunner leaping to his death from the nose.

Following the unveiling at midday, a second ceremony saw the curtain rise on another plaque half an hour later at the former Royal Naval Hospital in Queen's Road.

Opened in 1811 to cater for casualties of the Napoleonic Wars it was seldom in use 15 years later and was over the years variously used as a barracks and lunatic asylum. More recently it was an NHS psychiatric hospital before the building was converted into apartments.

Both plaques were unveiled by Rear Admiral Simon Charlier, Royal Navy, who travelled from London to represent the service, reflecting the significance of both the plaques and Yarmouth's frontline role as a witness to war.