The Queensferry Crossing looks remarkably like the earliest design for a bridge over the Forth at Queensferry, an Edinburgh University academic said today.
Bruce Gittings said the 199-year-old plans for a "bridge of chains" had made him - and his students - do a double take.
They were devised by Edinburgh-born engineer James Anderson who was inspired by his friend Thomas Telford's designs for the Menai Strait bridge in North Wales.
Anderson claimed his bridge would “facilitate the communication between the southern and northern divisions of Scotland”.
However, Mr Gittings said Anderson's bridge was never built and would probably have been over ambitious for its time.
The National Library of Scotland, which included the plans in an exhibition two years ago, said they were the earliest known.
Mr Gittings, of the university's school of geosciences, came across the “Bridge of Chains proposed to be thrown over the Frith of Forth” while the geographer was researching bridges to add to his online Gazetteer for Scotland - a project to record every settlement and landmark in the country.
He said: "When I saw the plans, I thought oh gosh, that does look remarkably like what's opening tomorrow.
"Some of my students also asked me if they were plans for the new bridge.
"The scale and construction are completely different but they do look very similar.
"If Anderson's bridge had been built, it is unlikely to have survived long.
"It would have been an enormous challenge and was ambitious for its time."
Mr Gittings said the fact Telford hadn't designed his own Forth bridge suggested he thought it wasn't possible at the time.
Anderson's bridge would have been a wooden or wood/iron roadway suspended by iron links.
It was estimated to cost between £175,000 and £200,000 - the equivalent of around £840 million today.
The Queensferry Crossing is a cable-stayed bridge, whose cables of steel wires hold up the deck.
It has cost £1.35 billion, including the main contract of £890 million.
Mr Gittings said: “His design was beyond the engineering capabilities of the time, as evidenced by the collapse of the Tay Bridge in a storm in 1879 and of the Chain Pier at Trinity in Edinburgh – on which Anderson also worked – in 1898.”
Anderson was born in the Old Town, the son of a textile worker.
He died at his home in the city in 1861 and is buried in Old Calton Burial Ground. Edinburgh University said the Gazetteer for Scotland - www.scottish-places.info - was the first description of Scotland to be published online in 1995 and remained the largest, with more than 25,000 entries.