For passengers of Britain’s luxury liners, it was an unforgettable part of the ocean crossing. The behemoths of the sea glided through the glens and highlands of Scotland, taking in some of the most spectacular Caledonian countryside as they progressed from Edinburgh to Glasgow through the engineering wonder of the age – the Mid-Scotland Ship Canal. Sadly, engineering practicalities and escalating cost estimates meant that a canal slicing Scotland in two never amounted to much more than architects’ drawings and official reports.

Many of the projects featured on the BBC 4 programme ‘Unbuilt Britain’ are staggering. A Victorian Channel Tunnel that would have linked Birmingham to Paris via London’s Metropolitan Line? A glass city for the centre of London or the complete demolition and rebuilding of Glasgow? I’d heard of most of these plans – many of them existing at the more eccentric end of a ‘can do’ spirit that marked the railway age.

One plan, however, completely amazed me. I’d never before heard of a plan to build a ship canal that would have been large enough to convey the largest dreadnaught battleships and would have sliced Scotland in two. The Mid Scotland Ship Canal would have linked the Forth and Clyde rivers via Loch Lomand. It would have been an engineering marvel and one of the most expensive civil engineering projects ever untaken.

A cursory glance at a map of Scotland quickly reveals where the backers of this project got their inspiration. The Firth of Forth and the Firth of Clyde bite into the Scottish mainland, squeezing the country until there are only 40 or so miles of land separating the Irish and North Seas. With trade across the Atlantic from Glasgow booming, it seemed natural to promote a scheme that would give the second city of Empire easy access to European markets.

A ship canal was also promoted by some in the defence establishment who foresaw great advantages in cutting days from the northern passage of battleships in the Royal Navy. They cast envious eyes over Germany’s Kiel Canal, which, since its opening in 1887, had linked the North and Baltic Seas and given the Kaiserliche Marine a decided advantage in a crucial theatre of war.

Of course, with such an obvious route, the canal mania had already struck. The Forth and Clyde Canal opened in 1790, taking 35 miles to link the Forth and Clyde between Grangemouth and Bowling. This canal had been successful, but was now far too narrow and shallow for modern shipping, let alone the behemoths of the Imperial Navy. The ship canal’s backers disparagingly referred to the Forth and Clyde Canal as the ‘barge canal’.

By the mid to late-nineteenth century, canals were enjoying a revival. These were not the quaint waterways winding through bucolic English countryside – they were megaprojects such as the Suez and Panama Canals that transformed the world and radically shifted patterns of commerce and shipping.

Even Britain saw new canal building with the Manchester Ship Canal. Opened in 1894, the Manchester Ship Canal enabled Manchester to bypass Liverpool and gave Cottonopolis direct access to the sea. What was good enough for Manchester was surely good enough for Glasgow and the Scottish lobby pressed hard for its sea link.

The first concrete proposals for the canal were put forward in a 1889 plan devised by Scottish engineers D&T Stevenson. The engineers put forward a choice of three routes from the Forth to the Clyde. This nineteenth century plan sought to avoid the River Forth and Glasgow to avoid engineering issues. A trade slump, cost escalations and the opposition of established interests in the Port of Glasgow put paid to the idea for over two decades.

By 1913, however, with the prospect of a war with Germany looming and many pressing demands on the Exchequer, the plan excited both hawkish demands for completion (as a vital part of British naval power) and more frugal calls for cancellation (on the basis that the vast sums of money would be better spent elsewhere). On 11 February 1913, a debate was held in the House of Commons in which the future of the Mid-Scotland canal was discussed:

“Mr. WATT asked the Chancellor of the Exchequer whether his attention has been called to the importance of the proposal for a Mid-Scotland canal, which would accommodate war vessels in passing from the Irish Channel to the North Sea.”

He was joined in his calls by Dr Chapple, who went on to ask the Secretary for Scotland whether: “he will endeavour to secure from the Development Fund a Grant of £900 towards the cost of boring along the route of the projected Mid-Scotland ship canal for the purpose of enabling the engineers to secure the data necessary to form an accurate estimate of the cost of constructing a short and safe route for British shipping for European and American traffic and for the Empire’s Navy.”

The response that came back was decidedly unenthusiastic: “The scheme referred to is so large in its scope and purpose as to suggest the necessity of caution in dealing with even such a preliminary survey as my hon. Friends contemplate.” till, nothing could stop the dreaming of the projects backers and, in 1917, a report was issued on the ship canal.

The proposal lumbered on into the inter-war years, being seen alternatively as a boost to northern commerce and a work creation scheme. The age of the container ship finally put paid to any prospect of a northern ship canal.