It's the anniversary of the Battle of Britain and we're celebrating the Supermarine Spitfire - the single-seat fighter plane credited with winning against Nazi Germany's Luffwaffe airforce in the first major campaign ever to be fought entirely by air forces.

The Spitfire was hugely popular in many Allied countries during and after WWII, and there were eventually 24 marks of the plane and numerous sub-variants in use up until it was retired in 1955 as new jet engines phased out propeller-powered aircraft.

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A restored Supermarine Spitfire takes to the skies Avspecs

Today, there are 235 Spitfires remaining across the world, and only 52 of them are airworthy.

A company called Avspecs in New Zealand specialises in restoring vintage and wartime aircraft, making each plane as authentic and accurate as possible, so that it will fly and be as good as a brand new plane straight from a factory.

Once restored, Spitfires sell for a minimum of £2m ($3.4m) each, while wrecks can be obtained for roughly about £700.

Check out the amazing photographs from Avspecs' award-winning Warbirds Restoration workshop in Auckland, where three different Spitfires, ranging from a mk.5 to a mk.14 are painstakingly being restored. You can read our interview with Avspecs' owner Warren Denholm about restoring Spitfires here.

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Repairing the wing frame Avspecs
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Close-up of a Spitfire wing Avspecs
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Working on the body of the plane Avspecs
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A sneak peek at the Avspecs' Warbird Restoration workshop Avspecs
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Sanding down a wing Avspecs
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Fitting casing over the engine of the plane Avspecs
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A close-up at the tail frame of the Spitfire Avspecs
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The cockpit of a Spitfire Avspecs
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Inside the cockpit Avspecs
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Inside the cockpit Avspecs
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Fixing the Spitfire's landing gear Avspecs
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Working on the propeller Avspecs
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Building parts for the Spitfire Avspecs
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Painting the Spitfire wing Avspecs
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The Spitfire starts to come together Avspecs
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Working on the Spitfire Avspecs
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Close-up of the Rolls-Royce engine Avspecs
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Testing out the Spitfire Avspecs
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Getting there Avspecs
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Preparing the pilot for take-off Avspecs
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Off we go! Avspecs
The majestic Spitfire flies again Scott Slocum
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The team behind Avspecs' Warbird Restoration of the Spitfire Avspecs