Georges Remi, the Belgian boy who would one day become Hergé and create Tintin, honed the skills that would give birth to the modern comic strip on the walls of a forgotten school scout hut in Brussels.

Yves Rouyet, a lifelong Tintin fan and local councillor, is campaigning to save the frescoes of adventuring boy scouts, native American Indians and knights, which are in desperate need of restoration after almost 100 years of being ignored.

“These murals are an essential moment in the history of comic strips,” said Yves Rouyet, “Hergé invented a manner of storytelling with drawings that had never been seen before”.

Thierry Scaillet, a historian and archivist from the Catholic University of Louvain said, “It is the oldest work by Hergé that we know of.”

The discovery of the work, neglected since the early 1920s, has all the hallmarks of one of the beloved Belgian boy reporter’s adventures. 

Mr Rouyet, a local historian, received a mysterious tip-off from a caller, who knew his journalist father was a comic strip expert, in August.

He investigated and the trail led him to the Institut St Boniface, the school in the Ixelles area of Brussels where a young Hergé studied, and a now disused scout hut on its ground. There he found a long lost artistic treasure that gives vital clues to the influences that gave birth to Tintin.

The 15-year-old Georges Remi was already showing the flair for action that would make him famous and his comic books among the most popular of the 20th Century. 

 “He created the modern comic strip, he invented the speech bubble, and you can see this in these murals. There are drawings showing scouts how to throw lassoos or put up a tent," he told the Daily Telegraph, "these walls are the beginning,”

If Tintin had found such a long lost treasure it would be the beginning of a great adventure. “I don’t know if that will happen to me,” the local historian joked, “but I hope so.”

Hergé’s scout masters recognised his prodigious talent and asked him to decorate the walls of the scout hut. Hergé painted a large map of Belgium and recounted the long scouting trips he enjoyed with his troop.

“Happily the murals were never painted over,” said Mr Rouyet, “and they were never destroyed but they have also never been restored. The school cannot afford to pay for the restoration so we must campaign."

Mr Rouyet said that Hergé got the confidence to pursue his career after his drawings were published in the school scout’s magazine. 

He hopes that once the murals are restored the school will allow visitors on special days such as the festival of comic strips in Brussels.

Belgians, like the French, take comic strips extremely seriously, referring to them as the “ninth art”. 

Hergé’s work is particularly sought after by collectors. A single original panel from the story Tintin On The Moon sold at auction for £1.3 million in 2016.