How some packaging nails saved Bell his telephone patent and his fortune

But Alexander Graham Bell's place among the greats was almost scuppered by one of his closest friend's attempts to show his fellow Scot's work off to a Glasgow audience.

New research by Professor Graeme Gooday, of Leeds University, reveals that in 1876 Lord Kelvin, the founding father of modern physics – at the time Sir William Thompson – had visited his friend Bell in America and brought two telephones back to Scotland, where he attempted to demonstrate them before they had been patented in the UK.

The demonstration failed, however, because vital vibrating parts had been nailed down to prevent them from being damaged in transit. Had the equipment worked it would have constituted "prior disclosure" and invalidated Bell's application for a British patent. That would have left the title of "inventor" open to countless other claimants.

Gooday, an expert in the evolution of electrical technology, said he discovered the remarkable incident while researching Bell's claim to have invented the telephone. He will deliver his findings in a lecture on Thursday at the National Museum of Scotland in Edinburgh.

Gooday said: "Bell is recognised as the inventor of the telephone because he was awarded the patent but the Bell patent was almost completely demolished in the UK by one unfortunate accident."

Gooday said that the Bell company later litigated against others who tried to sell telephones, many of whom claimed that the telephone was already in the public domain because of Thompson's failed demonstration. Bell's lawyers were forced to show that the Thompson incident showed no such thing.

He added: "In British law you could not patent something that had already been publicised as any prior public display would make patenting invalid.

"Bell's lawyers had to show that what Kelvin displayed in Glasgow was not the real thing but an early prototype. Had the patent been invalidated it would have been the end of the Bell fortune."

Bell's place in history was secured by his diligence in gaining the patents in both the US and the UK, both improtant commercial markets for the new device at the time. A plaque with the inscription "Inventor of the Telephone" has been placed outside his birthplace at 16 South Charlotte Street, Edinburgh.

At least four other inventors, including Frenchman Charles Bourseil, German Philipp Reis, Italian-American Antonio Meucci and American Elisha Gray have staked claims to their vital roles in developing the product along with the American Thomas Edison.

"Bell's recognition as such arose in part from the Anglo-American patent system's presumption that the award of any patent rights always had to be to a 'first and true inventor,'" Gooday said, "and also from the skill of Bell company lawyers in defending those patent rights against courtroom challenges by disputants who characteristically claimed a very different history of the telephone's invention.

"The one thing you could say about Bell is that he was the first to get a commercially viable telephone going. It would be difficult to contest that Bell is the most important figure in the history of telephony."

Bell, born in 1847, developed his interest in acoustics and sound transmission in part through attempts to communicate with his deaf mother.

On 7 March 1876, the US patent office issued Patent No 174,465 to Bell, covering "the method of and apparatus for, transmitting vocal and other sounds telegraphically".

n Prof Gooday will deliver his free lecture Patenting the Telephone: Legally Disputing an Inventive History at 3pm on Thursday in the Dunfermline Room at the National Museum of Scotland in Edinburgh.