Union canal tunnel.

Union Canal Tunnel, Falkirk.
Scotland Longest Canal Tunnel.
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In 1792, the same year as the Forth and Clyde was completed, the scarcity of coal in Edinburgh led the city fathers to look towards the rich Lanarkshire coalfields for future supplies.
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The advantages of a waterway linking the city to the west was obvious and several possible routes were surveyed between 1793 and 1797 by distinguished engineers including John Rennie and Robert Whitworth. Involvement in the French wars delayed the project and when planning was resumed in 1813 a plan by Hugh Baird was commissioned.


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This envisaged a line linking Edinburgh and Falkirk, where the new canal would join with the Great Canal as the Forth and Clyde was known. Work began in Edinburgh in March 1818 and continued, following the contours of the land right through to Falkirk, a total distance of 31 miles.
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The Forbes family of Callendar went to extraordinary lengths to ensure that the canal would not be visable from their estates. The campaign of opposition included producing a print and plan showing the 'detrimental' effect of the development which was sent to every Member of Parliament in Britain. It was successful and engineers were forced to cut a 690 yard tunnel under Prospect Hill.
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This involved blasting and digging through solid rock, and the 'dark tunnel' as it is known remains a marvel even in this high technology age. The squads of navvies engaged in digging and lining the channel were the same hard drinking, hard living gangs of displaced workers from the highlands and later from Ireland who had already made the Great Canal and would one day drive the railways across the length and breadth of the land.
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Although the canal was built without locks, a way needed to be found of linking the Union Canal with the Forth and Clyde Canal, a difference in height of 110ft where they met. The answer was a staircase of 11 locks over a half mile length of canal at Camelon near Falkirk.
This emerged into the Forth and Clyde just to the east of the Union Inn.
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Just 20 years after it was finished the railways started to take away the passenger and freight traffic its viability depended on, and it went into a long period of decline. This culminated in 1965 with the formal closure of the canal by Act of Parliament.

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Many barriers had to be overcome. A new stretch of canal had to be dug at Wester Hailes. And where it was cut by the M8 motorway the Union Canal was diverted a little to the west through a new channel and a bridge was created, entailing the lifting of the whole roadway.
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Most significantly, a way had to be found of linking the canals together in the absence of the 11 locks that used to do the job. The answer was an extension to the Union Canal leading to the top of the magnificent Falkirk Wheel, which was opened by the Queen in May 2002, marking the completion of the Millennium Link.