As with many of the blue-chip collector cars from last century, the early Mercedes-Benz S-Type, introduced in 1927, was inherently a race car that could be transformed into a powerful, road-going calling card for society’s most upwardly mobile. On December 11, one of the only 174 examples of the model ever made will cross the auction block through Bonhams. Already a rarity, this particular S-Type also has the distinction of being owned by Academy Award–winning actor Peter Ustinov before it was primarily parked at the National Motor Museum in England for more than five decades.

Born a year after the name Mercedes-Benz was officially adopted, the S-Type became the initial springboard for the automaker’s legacy. The model owes much of its existence to Porsche, Ferdinand Porsche, that is, prior to the  founding of his eponymous marque. Although the “S” in the car’s name stands for “Sport,” it could just as easily be for “Supercharged,” since, as the Bonhams lot description denotes, “Daimler-Motoren-Gesellschaft [the company’s prior iteration] had introduced the world’s first supercharged production cars.” And Ferdinand was all for it.

The chief engineer for Daimler in the mid-1920s, Porsche was responsible for the S-Type and its motorsport prowess, demonstrated convincingly at the Nürburgring’s premiere race in 1927, where one of the two S-Type cars entered took first overall. According to Bonhams, for that model, “the UK designation was 36/220,” and the engine given it was a 6.8-liter six-cylinder mill that, with the supercharger, delivers up to 180 hp.

As noted by Bonhams, the example on offer, chassis No. 35952, is a 36/220 S-Type Four-Seater Sports Tourer that left the factory in 1928 and was initially under the ownership of Mr. AW Dowding. The auction house also mentions that no information is available as to who crafted the original body. After Dowding, the ownership trail is largely lost—save for a couple of very brief ownership stints—until Ustinov became its steward in 1951.

Starting in 1955, the acclaimed thespian, twice named Best Supporting Actor by the Academy of Motion Picture Arts and Sciences for his roles in Spartacus and Topkapi (films of 1960 and 1964, respectively), had the car displayed at what was then England’s Montagu Motor Museum. He then gave it to the facility’s later incarnation, the National Motor Museum, in 1973, where it has resided ever since.

Interestingly, when the car first began its tenure as an exhibit, it featured a two-seat configuration. That was changed with the only restoration Bonhams mentions, one undertaken by the National Motor Museum. The task included replacing the two-seat body with that of a four-seater built especially for the refurbishment by coachbuilder Rod Jolley. The purpose of the restoration was to get the vehicle in road-ready condition for Lord Montagu to enter it in a 1986 rally, which was then commemorating 100 years of the automobile—a timeline considered by many to have begun with Karl Benz’s Patent Motor Car. Montagu piloted it again in the 1987 Mille Miglia, and the vehicle has likely not been on the road again.

This example’s nearly 40 years of dormancy means that a considerable amount of attention is needed. The laundry list includes plenty of TLC for the engine—probably requiring a comprehensive rebuild—and addressing structural compromises. The Bonhams lot description states: “The bulkhead has never been fitted correctly as it was rushed for the Mille Miglia, while the running boards are only loosely attached for the same reason . . . The wiring harness was not fitted, the electrics merely being wired to make them usable.”

This car is for the collector who not only covets one of the most important models in the history of one of the world’s most influential marques, but also cherishes a challenge. That opportunity will be knocking at the Bonhams Bond Street Sale that takes place on Thursday in London.

Making this lot even more noteworthy is the fact that chassis No. 35952 has been highly reclusive up until now. In fact, Tim Schofield, senior specialist at Bonhams, tells Robb Report that this is “the first time in over seventy years this supercharged supercar of its day has been publicly available.” Just one more reason why its estimated value is between $1.7 million and $2.3 million.

Click here for more photos of this 1928 Mercedes-Benz 36/220 S-Type.