Lotus is celebrating its 70th anniversary and one important thing is missing from the festivities – its first car. The company is now trying to fix that by launching a search to find the 1948 Lotus Mark I.

Billed as the “elusive Lotus ever,” the Mark I was hand-built in a London garage by Colin Chapman. Once the car was completed, he entered the model in a number of events and found “immediate success.” Unfortunately, Chapman didn’t know Lotus would eventually become a world-renowned company so he sold the car in 1950 as he focused his attention on the Mark II.

The car was advertised in Motor Sport magazine and was bought for $177 (£135 / €150) in November of that year. However, the only thing known about the buyer is that they lived in the “north of England.”

The car’s whereabouts have remained a mystery since then, despite a number of efforts to track it down. There are a few possible explanations for this and one theory suggests the car might have been shipped out of the United Kingdom. Of course, it’s also possible that the Mark I could have been scrapped by someone who didn’t know about its significance.

Regardless of what happened, the Lotus Mark I was a “re-imagined and re-engineered” version of the Austin Seven. Among the upgrades are a reinforced chassis and lightweight body panels which can be easily removed and replaced. The Mark I also featured an extended rear end and two spare wheels.

In a statement, Colin’s son, Clive Chapman said “The Mark I is the holy grail of Lotus’ history. It’s the first time that my father was able to put his theories for improved performance into practice when designing and building a car.”