Although various people had put money into the enterprise it still remained the property of Hugh Myddelton, which was far from satisfactory from the point of view of its biggest investor, King James. Therefore in 1619 the King issued letters patent that converted it into a new legal entity known as ‘The Governor and Company of the New River’, with Myddelton as its first Governor and a specified number of elected officers. At the same time the King took the opportunity to slip into the founding charter a clause giving the company an effective monopoly of the supply of any new water supplies into London and Westminster. That privilege had never been granted in the original Act of Parliament but by 1619 James was the biggest shareholder so he was cleverly protecting his own investment without having to argue the case with a dissolved Parliament. The shareholding in the company was inherited by James’s son, Charles I, who sold his part in 1631.
Later in the 17th century the New River’s network was extended to supply Covent Garden and as far as Piccadilly, St. James’s, and Whitehall. By the time water arrived at the Round Pond reservoir it was half-way down Islington Hill. That was sufficient for water to flow downhill from there to customers in the nearby City but lack of pressure provided only a trickle of water to the new suburbs to the west. As a solution the water engineer George Sorocold built a wind- and horse-powered mill to pump water up to a reservoir further up the hill to provide a steeper gradient for those more distant districts. The mill was only partially successful and replaced by an improved structure in 1720. That in turn was succeeded by an early coal-powered engine in 1760.
Over the centuries water continued to flow along the New River from Hertfordshire to Islington. New River Head became a favourite place for Londoners to take a walk, a pleasant spot from where they could gaze down over the entire metropolis, from Mile End in the east to Westminster in the west and Southwark in the south. It was most probably in 1665 that the artist and engraver Wenceslaus Hollar escaped to Islington from the plague-ridden London and whilst there sketched evocative pictures of New River Head. In around 1750 the Venetian artist Canaletto sat on Islington Hill to take in the incredible panorama and produce one his celebrated London views, with the New River reservoirs in the foreground.
In 1759 a competition was held to design a new bridge over the Thames at Blackfriars. All the famous architects of the time submitted plans but against the odds the chosen entry was by an unknown Scottish design student. His name was Robert Mylne. Propelled to fame by London’s new bridge, he went on to become a successor to Sir Christopher Wren as Surveyor to St. Paul’s Cathedral (during which time he arranged Nelson’s funeral), the engineer of various canals and harbours, and the first of a dynasty of engineers to the New River Company.
The company required a continuous supply of elm to replace rotten sections and to extend its system as London expanded. These elm trunks were brought by boat along the Thames and landed at the company’s wharf near Blackfriars (now the site of the City of London School). On Christmas Eve 1769 the premises burnt down and Mylne’s first project was to replace them with a new complex of fine offices, workshops and stables. He continued as the company’s engineer until the age of seventy-seven, a few months before his death at his home at Water House, New River Head. Amazingly, much of London’s water supply flowed through his basement!
When the anti-Catholic Gordon Riots took place in July 1780 it was thought the rioters planned to set the Bank of England alight and cut the New River to hinder the fire fighting. Troops were therefore stationed at New River Head and other vulnerable parts of the system such as wooden aqueducts at Highbury and Bush Hill, Enfield.
Such was Robert Mylne’s dedication that he named his second son after one of the sources of the New River, at Chadwell. William Chadwell Mylne was to play a prominent role at the New River Company. As London and its population grew during the early 19th century, as well as the demand for the New River Company’s water, William Chadwell Mylne recommended to the company’s Board the creation of two holding reservoirs beside the canal, north of the village of Stoke Newington. They were created between 1830 and 1833. London Bridge was being rebuilt at the same time to replace the one that had stood since 1759 (of which parts had survived since medieval times). Mylne used wood from the old bridge to line the reservoirs at Stoke Newington in order to protect the banks.
When it was first created the canal followed the contours of the land through which it passed so that it remained on a slow decline from Hertfordshire to Islington. That created many loops and an original length of at least forty-two miles. Shortening the length (and therefore the cost of maintenance) began as early as 1618, and continued over the decades, by the creation of tunnels, embankments and taking it through pipes.