It is thought to be the most important car in British motoring history and once proved its reliability by driving from London to Glasgow and around Scotland – non-stop.

The famous Silver Ghost, known by its registration plate AX 201, was built by Rolls-Royce in 1907 and soon earned global fame for its quietness, luxuriousness and price.

It is considered something of a holy grail among enthusiasts and is thought to be the most valuable motor in the world, with an insured value of £27 million.

Last year, Rolls-Royce launched a new, limited edition car to commemorate the history of AX 201, named the Silver Ghost Collection.

Just 35 were produced and are on sale for hundreds of thousands of pounds.

But a curious fact about the car’s famous Spirit Of Ecstasy hood ornament has come to light almost a year after it first launched – and one that Rolls-Royce has not even advertised to the public.

The bottom of the statue on the bonnet of the 35 Silver Ghost Collection models contains a small copper ingot, marked with the AX 201 insignia of the original car.

Rolls-Royce enthusiast Ruth Blair has revealed the copper is, in fact, taken from a pipe on the original 1907 car that has been melted down and placed on to the 2018 model in homage to the Silver Ghost.

Mrs Blair, a charity fundraiser who has a farm near Cumbernauld, said she acquired copper from the original Silver Ghost after it was reconditioned in 1988 by Rolls-Royce heritage experts Paul and Andy Wood.

The brothers replaced some copper piping from the engine bay of AX 201 and various steel components, and kept them for 20 years, waiting for an appropriate way to use them.

In 2007 they gave the metal to Mrs Blair, who at the time was creating a miniature Rolls-Royce for children that she eventually sold to raise money for charity.

Realising the immense value of the parts, she sold them back to Rolls-Royce in 2017 for an undisclosed amount of money and suggested the manufacturer create a limited edition tribute car to its most famous model.

The company then commissioned 35 cars and has sent them all over the world to be sold to wealthy collectors, investors and enthusiasts.

Last night, a sales representative of the Leven Car Company said the source of the ingot was kept a secret until salesmen could be sure a potential buyer was serious about purchasing the car.

Details of the car were also kept out of the public domain to protect the Rolls-Royce brand.

A spokeswoman for Rolls-Royce said: “Thirty-five of the extraordinary and exceptional Silver Ghost Collection have been created by Rolls-Royce Motor Cars.

“Individually, as customers purchase these cars, they are intrigued to discover the provenance of the small copper ingot at the foot of the Spirit Of Ecstasy, and are surprised and delighted at its origins.”

After researching the car on its release last year, Mrs Blair realised the company had not advertised that the copper at the base of its hood ornament had come from the original AX 201.

She told The Herald she acquired and then sold the copper from the Silver Ghost, and that it had been kept a secret from Rolls-Royce’s own potential customers.

Her husband, John Blair, who is a former car salesman, travelled to the Rolls-Royce factory at Goodwood, West Sussex, while the cars were being manufactured.

He learned that even the engineers working on the Silver Ghost collection’s construction had not been told by the company’s executives where the materials had come from.

To practise creating a copper ingot, and not wishing to use the precious century-old copper, Rolls-Royce bought some of the material from a local scrapyard to create a prototype of what would become the limited edition Spirit of Ecstasy, she said.

Now only one of the cars remains in the UK, at the Leven Car Company in Edinburgh.

Mrs Blair still owns steel wheel assembly nuts, coach bolts and a starting handle spring from the Silver Ghost.

And she says she is looking for a partner who may be able to help her rework or redevelop them.

“I originally gave them all the parts – the steel and the copper – and they gave me the steel parts back,” she said.

“John took the parts down to Manchester, and everyone seemed to have an interest in the copper rather than the steel.

“If you see a picture of AX 201, you’ll see it’s got circular bolts around the wheels, and that’s it.

“The car was restored but they tried to keep it as original as possible so they only took off parts that were well and truly gubbed.”

Mrs Blair also owns the registration plate 201 AX, which is a reversal of the famous car’s plate.

She says she has had “loads” of Rolls-Royces, and that her fascination with them came from travelling in the back seat of a Rolls-Royce Corniche when she was a child.

“I had two brothers that were car mad, and I’ve always loved cars,” she said.