Many motorcyclists over the years have wished for more "presence" with which to balance the inequities of the road-going pecking order, but until I wandered into the newly opened Vespa Museum near the Australian Albert Park Formula One Circuit this week, I had no idea that there had ever been a production two-wheeler which could command complete respect from fellow-roadgoers (apart from maybe a Harley-Davidson with open pipes).

In the late 1950s, French Vespa licensee ACMA (Ateliers de Construction de Motocycles et Automobiles) produced 500 (perhaps more) examples of this military Vespa with integrated M20 recoilless rifle / light anti-armor cannon, in two production runs in 1956 and 1959.

Though there's a lot of dubious information on the Vespa 150 TAP on the internet, much of which claims the rider could fire the M20 on the move, a close inspection of the 150 TAP convinced me that it was not set up to be fired from the scooter, partly due to the lack of access to the firing mechanism of the American-made M20 recoilless rifle, partly due to its mounting slightly across the frame (which would no doubt have resulted in some handling difficulties for the rider of the lightweight 150 kg scooter – recoilless is only a relative term in this instant), and partly due to the thin saddle covering, which might well have resulted in a fate worse than death. There's also the slight issue of aiming the M20 – not much point in getting that much firepower in place with limited ammunition and wasting it.

The idea behind a military Vespa was not entirely new, even though the iconic freedom machine of the Baby Boomers was less than a decade old when it was pressed into military service.

The Italian Vespa factory had developed a Vespa Force Armate (Armed Forces) prototype between 1949 and 1951 which boasted many advantages over the military motorcycles of the time: lighter weight; better low speed maneuverability; lower fuel consumption; the ability to carry a spare wheel and to change it rapidly on either end (if you think fixing a motorcycle tire is problematic, try doing it while people are shooting at you); and thanks to the scooter's reliable drive train (chains were one of the weaknesses of motorcycles of the period), less likelihood of being stranded in a hostile environment.

Vespa's 150 TAP (Troupes Aéro Portées)

Vespa's factory-developed Vespa Force Armate prototype was envisaged with a variety of options, including mounting a submachine-gun on the handlebars, a radio under the saddle and an armored leg shield.

Though NATO trials showed the Vespa Force Armate was only 3 mph (5 km/h) down on the much larger traditional military bikes of the time in terms of top speed, and resulted in glowing appraisals. But after more than two years of negotiations, Enrico Piaggio canned the model. In a letter sent by Piaggio himself in 1952, he concluded he was “not interested in canvassing for State Orders since we know that its organs pay low prices and late” and that he was convinced that “the military are not worth the time of day.”

Hence when the French military decided it wanted a better mobility option for its airborne special forces ("Troupes Aéro Portées", hence the subsequent “TAP” acronym) than its existing American-made WWII Cushman scooters for the Algerian War, it organized a competition between French manufacturers for a replacement model.

In the end, it boiled down to a three-way shoot-out between prototypes based on the Valmobile 100, the Bernardet 250 and the Vespa. French Vespa licensee ACMA won the gig.

Despite an unmistakably different profile, the Vespa 150 TAP differed little from the Vespa scooter of the time. It used a 150cc two-stroke engine derived by ACMA from the Vespa 125 motor, with different bore and stroke to the Vespa 150 engine from the factory.

Vespa's 150 TAP (Troupes Aéro Portées)

Other than the engine, plus the M20 light anti-armor cannon, rack and ammunition mounts, the only major differences to a standard Vespa were a strengthened frame and lower gearing which gave it a top speed of just 40 mph (64 km/h).

The TAPs were designed to be dropped into theater by parachute on a palette, protected by hay-bales, fully assembled and ready for almost immediate action. As such, the TAP offered a highly mobile lethal capability with which to counter guerrillas – the M20 was originally designed as an anti-tank weapon and using a HEAT warhead, it was claimed to be capable of penetrating 100mm of armor and striking from a distance of 7,000 yards (6.4 km). The 150 TAP was often deployed with a trailer, which was used for additional supplies and a lightweight stand for the M20.

Though the M20 with HEAT warhead was found to be ineffective against up-armored T-34 tanks during the Korean War, it was ideal against more makeshift field fortifications and used quite effectively during the Algerian and Indochine conflicts (the second ultimately becoming the Vietnam War).

Alternative warheads were available for the M20, one of which could lay a smokescreen – another helpful capability in the asymmetric conflicts in which it was used.