Attention! Form follows function in this season’s best battlefield-inspired outerwear.

In the world of menswear, there are only two influences that really matter: sport and the military. Sport has given us such classics as the baseball cap, the polo shirt and the tracksuit, to name but a few. The military, meanwhile, has provided us with the inspiration for almost our entire outerwear wardrobe.

To understand why the armed forces have been responsible for so many of the biggest innovations in menswear, we only need to remember that necessity is the mother of invention. A huge number of everyday technologies were forged in the fires of conflict, among them GPS, superglue and the microwave oven. Clothes are no different, and many of the little details that we see on outerwear were originally designed with the battlefield in mind: epaulettes were a way of denoting military rank, while the buttons on a peacoat were displaced to the side and widely spaced so that they were less likely to get caught on the ropes of a ship.

With military-inspired outerwear once again back on the fashion agenda – so many designers embraced it this season that we named it one of our seasonal Trends – now seems the perfect time to rifle off a few of the old classics.

Early aviator jackets were originally designed to keep WWI fighter pilots warm in cockpits that were open to the elements. As such, they were fitted with thick shearling collars and were cropped at the waist to allow for easy movement while sitting down. While this smart Mortimer jacket is actually a modern take on one of Belstaff’s early motocross jackets, it shares a lot in common with an early 20th-century aviator jacket. The main difference is the material: rather than heavy leather, this one is cut from water-repellent waxed cotton.

The modern peacoat – double-breasted and cut short in the body – is inspired by coats originally issued to the US Navy after the American Civil War, which were in turn based on longer coats worn by British sailors prior to that, and Dutch mariners before them. The collar was designed so that it could be turned up against the elements. This standout version from Burberry’s military-heavy autumn collection adds a formal edge to the garment with decorative gold buttons and blood-red piping reminiscent of an officer’s uniform, while the cashmere-wool blend offers a supremely soft handle.

The original M-1948 fishtail parka was produced by the US Army for just a single year, in 1950, before being replaced by the cheaper M-1951 model on the outbreak of the Korean War. That wasn’t the end for it, though, as it was swiftly adopted by the mod movement of the 1960s, and was subsequently passed through the hands of a number of youth subcultures. Balenciaga’s modern update to the classic parka keeps its blend of style and practicality, while adding a shearling-lined hood for extra warmth.

The MA-1 flight jacket was originally designed by the US Air Force in the 1950s as a solution to the emerging issues of high-altitude, jet-powered flight. Cut from water-resistant nylon and with thick synthetic padding and voluminous sleeves, it kept jet pilots warm without weighing them down or restricting their movement: all qualities that made the garment wildly popular with civilians, too. Casely-Hayford’s take on the MA-1, exclusive to MR PORTER, takes the traditional design and amps it up with a sleek army-green satin finish.

This military classic takes its moniker from the Belgian town of Duffel, which also gives its name to the heavyweight woollen material from which the coats were made. Duffle coats were first issued to Royal Navy sailors prior to WWI, but their distinctive toggle fastenings are now more closely associated with preppy students, Britpop stars and Rive Gauche beatniks. Speaking of Paris, this season’s standout duffle comes from one of our favourite Parisian brands, Sandro. With sleek, leather-trimmed closures and a semi-fitted cut, it’s suited to the city without doing away with the garment’s maritime heritage.

It’s hard to believe that a garment as sleek as the trench coat was ever intended to be worn in a trench, but there you go. While the design for the officer’s garbardine raincoat was first submitted to the British War Office back in 1901, the coat got its name after being worn in the trenches of WWI. This modern take from Scottish outerwear specialist Mackintosh swaps out the traditional material for resilient Storm System wool, but otherwise retains the trench coat’s classic design.

The M-1965 field jacket was introduced by the US Army in – you guessed it – 1965, and was originally intended to be worn by soldiers in Vietnam. But while the patch pockets and epaulettes act as a reminder of its provenance, this is a jacket that has long transcended its military origins, and is now more reminiscent of 1960s counterculture. Tom Ford’s is a typically luxurious take on the style, with a neatly tailored cut and lustrous silk lining.

**Shop more military jackets here **