The first modern canal, built in the 1760s by the Duke of Bridgewater, was dug by local labourers, many of them seasonal farm workers. When the work was finished, they found themselves in demand on other canal projects. The earliest professional navvie on record was John Walker, who said in 1801, "'I worked upon the Duke of Bridgewater's Canal, and since have worked upon several.''

As more canals were built, the workforce grew. Many contractors continued to hire unskilled farm workers, who could be paid less than the professionals. Yet it only took a few months to turn an unskilled labourer into a professional navvie. The labourers preferred digging canals to irregular and badly paid farm work. In any case, these were often men who were too drunk and disrespectful to be hired by farmers. One contractor, quoted in Dick Sullivan's history, Navvyman (1983), said of his workers, "They appeared to me the same as a dog that had been tied up for a week. They seemed to go out of their way to commit outrageous acts."

Building methods

After digging a deep cutting, the navvies made its base and sides watertight with thick coatings of "puddle", which an 1805 manual defined as "a mass of earth reduced to a semifluid state by working and chopping about it with a spade, while water just in the proper quantity is applied".

When a tunnel needed to be dug for the canal, the route was marked out on top of a hill. The men then dug ventilation shafts from above, as well as drainage shafts below the line of the tunnel. The tunnel itself was hacked out with picks and blasted with gunpowder. Tunnelling was the most difficult and dangerous part of building a canal, with the ever present dangers of flooding and roof collapses. The 2,880 yard-long Harecastle tunnel, on the Trent and Mersey canal took more than eight years to build.

The tunnels were usually lined with bricks, made from local clay if it was available. In stone country, stones were cut and shaped in local quarries.

Irish navvies

In the 1790s, when canal building was at its height, the war with France drew surplus English labour into the Army. Now there was an influx of Irish labourers, arriving from Ulster through the ports of Liverpool and Glasgow. Among the Irish newcomers were the notorious William Burke and William Hare, who worked on the Edinburgh-Glasgow canal in 1818. Burke and Hare then settled in Edinburgh, where, in 1827-8, they murdered 16 people in order to sell their bodies to a medical school, for dissection.

As drunk as a navvy

The men earned a reputation for drunkenness and violence, leading to the expression "as drunk as a navvy". Canal historian Charles Hadfield quoted an account of a mob of navvies terrorising the village of Bardney in Lincolnshire in the early 1800s:

They... attacked the "Bottle and Glass" public house - fetched the barrels of beer out of the house... and drank the ale... The constable of the village was called out, but he alone was of no use, as they would have attacked him at once; he made his escape with difficulty.... Thirteen constables were sent for from Horncastle, they also were useless, and had to go home again - one of them so much injured that he died from the effects afterwards; the cavalry were then sent for... they filled three carts with the rioters, whom they carried away with them...

Charles Hadfield, British Canals, 1959