100 years of the trench coat: What World War-I lent fashion

It seems only fitting that British brands Aquascutum and Burberry both lay claim to the trench. Designed for the bunkers during World War I, a fracas around its origins clearly illustrates the importance of this classic coat. After all, if you want to earn style stripes, your roots must lie in pure functionality.

When the heavy serge coat or the greatcoat was found to be unsuitable for the battlefield, it was replaced by jackets in the lightweight, waterproof fabric gabardine which had been developed by Thomas Burberry in 1879. In 1901, he submitted a design for an army officers coat to the War Office. And supplied about half a million during the war. Around the same time, Aquascutum founder John Emary also worked in collaboration with the British military to create a garment that offered greater protection for the soldiers. On the hundredth anniversary of the war and of this classic coat, I think it is important to remember why it remains a fashion staple, and how it got its name. To suit the needs of the Great War, the coat was modified to include shoulder straps that allowed for "the attachment of epaulettes or other rank insignia".

Popular myth had it that the D-ring on the belt was for the attachment of hand grenades. But the more mundane reality is that it was used for tying map cases and a utility pouch. Trench coats also had large pockets for maps and cleverly placed flaps - like the gun flap on the left shoulder to prevent rain from slipping into the jacket. The fact that the trench coat was designed for the battlefield is the reason it works wonderfully for civilians, too -- even in times of peace. When you overlay with a trench, you have a place for everything, especially with deep pockets that allow you to carry a wallet, two phones, three sets of keys et al, without anything falling out -- a common problem men have with the current range of slim fit pants. For women, it has the advantage of versatility. The coat works wonderfully with all styles (try it with a Nappa Dori messenger bag or a Hermès Birkin). Sling it over a saree or an LBD to add an edge.

This transition was the focus of the exhibition From Field to Fashion that ran in Thomas Burberry's home country, Hampshire. Concluding today, it featured an authentic World War I Burberry cavalry trench coat as well as the one actor Marlene Dietrich wore in the 1948 film A Foreign Affair. It also featured coats by Jean Paul Gaultier, Comme des Garçons and Viktor & Rolf.

Much as I hesitate to distil fashion down to the tag of "the one big thing you must own this season", I think it would be fair to add the classic trench to your list of investment pieces. Especially this winter. It doesn't have to be any of the big brands -- you will find high street versions as well. As Simon Armstrong, who writes for the BBC network, put it so aptly: "In fashion terms, the trench coat has gone on to win the style war."

How to know you are wearing an original: The ten elements of a classic trench coat

1. Raglan sleeve

2. Epaulettes

3. Storm flap

4. Throat latch (strap and buckle system)

5. Belt with D-rings

6. Storm pockets

7. Back storm cape

8. Sleeve straps

9. Deep vented back

10. Double breasted - traditionally with 10 buttons

(Source: The Trench Coat exhibition: From Field to Fashion)