A £1m reward is being offered for the person responsible for the safe return of a lost briefcase belonging to an executive of one of Scotland's oldest companies that contains scientific papers that he says could bring "vast amounts of wealth" to Scotland.

Dickie Bingham, chairman of Edinburgh-based tech investment firm British plc says he "stupidly" lost the crocodile leather briefcase on an Edinburgh tram on Monday morning.

He said its value comes in a scientific paper that links together all physical aspects of the universe from the sub-atomic scale - which he says is one of the major unsolved problems in physics.

Though invisible to human eyes, sub-atomic particles have been called the building blocks of matter and may be the key to understanding the nature of our universe.

Mr Bingham said the papers were crucial for the Scottish economy as the spin off of what he called Nobel Prize potential research which would bring many jobs to Scotland and was "important to the economy".

He says to claim the reward, the case and all the contents can be taken to any Scottish police station with contact details included. In the absence of contact details, a charitable donation of £1 million, will be made to benefit the people of Scotland.

Mr Bingham said he would be happy to present a cheque to the finder in association with Edinburgh Trams.

British plc, formed in 1896, is a normally publicity shy firm that "discreetly" invests in what it calls "disruptive innovations that alter the way that consumers, businesses and industries operate" including artificial intelligence, extended reality, and quantum technology.

"It was lost by my own stupidity," he said. "It is the most expensive tram ride I will ever take."

Mr Bingham had been travelling from a breakfast meeting at the University of Edinburgh, when he inadvertently left his briefcase on a tram he took to the airport between 9am and 10am on Monday.

The briefcase contains a number of items, including a set of five annual diaries for the years 1996 to 2000 and a letter to Mr Bingham from Yorkshire Ripper Peter Sutcliffe (below which he intends to donate to the National Museum of Scotland.

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But it is the scientific papers that could be "crucial for the Scottish economy" that he is most concerned about having returned.

"It is a theory of everything that covers the sub-atomic world. This is potentially Nobel Prize-winning documentation.

"It basically shows how the universe works. We think we may have cracked it.

"That is why it is crucially important. £1m sounds a lot but it is petty cash compared to the value of what this could be. "This is crucial to the Scottish economy. When we get the patent it will bring in substantial jobs in terms of scientific developments. It is a highly prestigious thing and it would lead to substantial rewards."

He said he had contacted Edinburgh Trams for help but heard "absolutely nothing" and has now made an appeal to the company's chief executive.

"I told them if the suitcase is handed in I am happy to be photographed with a large cheque. And I heard nothing from them," he said.

The theories of modern physics have given scientists a new understanding of how the universe works, but the current ideas are not able to solve some of the biggest scientific puzzles, such as how the universe as we know it came into existence.

All of the forces we experience every day can be reduced to just four categories: gravity, electromagnetism, the strong force and the weak force.

Last year, an international team of scientists, working on a project in the United States, say they discovered strong evidence for the existence of a new fifth force of nature.

The Fermilab Muon g-2 experiment finds strong evidence for new physics

They say some sub-atomic particles - called muons and are heavier than electrons - do not behave in a way predicted by current theories of physics.

A fifth fundamental force might help explain some of the big puzzles about the Universe that have exercised scientists in recent decades.

The British funders of the research said that scientists were “on the precipice of a new era of physics”.

Scientists at Fermilab, a particle accelerator just outside Chicago, have got a result that might take the world a big step forward in answering those questions.

It came after physicists working at the LHCb experiment at the Large Hadron Collider described results that could point to a new particle and force.

Edinburgh Trams were appoached for comment.