The original timber bridge was replaced by a steel structure in 1938, designed by Crouch and Hogg, which included a control box, as levels of traffic on the road and canal were increasing.

In 1844, the channel was made deeper and wider when barges pulled by horses were replaced by steam tugs, and there is evidence that the building once included four stables.

The A82 road crosses the canal on a swing bridge, at the foot of the five locks that rise through the centre of the village of Fort Augustus.

[18] At the top of the locks, a road beside the canal is spanned by a railway bridge, which was constructed to carry an intended line from Fort Augustus to Inverness.

Neptunes Staircase was originally fitted with 36 capstans each of which had to be rotated 20 times to operate the lock gates and sluices, but progress through the structure was sped up in the 20th century when the flight was mechanised.

[49] Engineers started to look at the feasibility of a canal to connect Loch Linnhe near Fort William to the Moray Firth near Inverness in the 18th century, with Captain Edward Burt rejecting the idea in 1726, as he thought the mountains would channel the wind and make navigation too precarious.

[50] The Commissioners of Forfeited Estates had originally been set up to handle the seizure and sale of land previously owned by those who had been convicted of treason following the Jacobite rising of 1715.

[51] By 1773, they had turned their attention to helping the fishing industry, and commissioned the inventor and mechanical engineer James Watt to make a survey of the route.

He emphasised the benefits to the fishing industry, of a shorter and safer route from the east to the west coast of Scotland, and the potential for supplying the population with cheaper corn, but again, thought that winds on the lochs might be a problem.

Laws had been introduced which sought to eradicate the local culture, including bans on wearing tartan, playing the bagpipes, and speaking Scottish Gaelic.

[53] The engineer Thomas Telford was asked to investigate the problem of emigration in 1801, and in 1802 published his report, which suggested that the main cause was landowners who had previously kept cattle creating vast sheep-farms.

Realising that direct government action to confront the issue would be seen as interference, he therefore suggested that a programme of public works, involving roads, bridges, and canals, would be a way to provide jobs for people who had been displaced by the sheep farming, and to stimulate industry, fishery, and agriculture.

[54] Telford consulted widely with shipowners, who favoured a canal instead of the hazardous journey around the north of Scotland via Cape Wrath and the Pentland Firth.

[56] The canal, as well as a number of projects to build roads, harbours and bridges, was the first time that public works of this sort had been funded by the government.

Telford had convinced them that it was feasible, and that employing local people on it would help to stop the tide of emigration, but no one considered whether it would pay its way when it was completed.

3. c. 102) was passed to authorise the project, and carried the title: An Act for granting to his Majesty the Sum of £20,000, towards defraying the Expense of making an Inland Navigation from the western to the eastern Sea, by Inverness and Fort William; and for taking the necessary steps towards executing the same.

At the time, Telford's scheme for the development of the Highlands was the largest programme of works ever undertaken for a specific area in Britain.

He visited the Highlands twice a year, to plan the work and inspect the progress, and was always on the move, to the extent that the Canal Commissioners allowed him to choose the dates when he would find it convenient to meet with them.

[62] In the Highlands, Telford faced a number of problems, in that the canal was to be built in an area where people lived a subsistence lifestyle, managing by keeping a few cows and paying low rents.

[66] The number of men employed fluctuated widely, not least because many would take time off to attend to peat cutting, herring fishing or harvesting.

It was 800 by 140 yards (730 by 130 m), and construction was aided by the fact that its bottom was above the level of low tides, and so it was relatively easy to keep the works dry.

The road from the basin into Inverness was renamed Telford Street, and Simpson and Cargill built a row of houses for overseers and contractors to live in, including themselves.

By the time the banks were completed, the price of foreign timber to construct a coffer dam had risen so much that work was postponed.

The peninsula was allowed to settle for six months before excavation began, and a 6 hp (4.5 kW) Boulton and Watt steam engine was used to keep the lock pit dry during the work.

[75] By early 1810, the steam engine at Corpach was ready, and the coffer dam to enable the sea lock to be built was completed by mid-1810, after considerable difficulty.

[81] The work was designed by Telford's associate James Walker, carried out by Jackson and Bean of Aston, Birmingham and completed between 1843 and 1847 at a cost of £136,089.

[83] There was an upsurge in commercial traffic during the First World War, when components for the construction of mines were shipped through the canal on their way from America to “U.S.

Naval Base 18” (Muirtown Basin, Inverness), and fishing boats used it to avoid possible enemy action on the longer route around the north of Scotland.

British Waterways, who work with the Highland Council and Forestry and Land Scotland through the Great Glen Ways Initiative, were hoping to increase this number to over 1 million by 2012.

[89] There are many ways for tourists to enjoy the canal, such as taking part in the Great Glen Rally, cycling along the tow-paths, or cruising on hotel barges.