The new Thames Navigation Commission took its powers from an Act of Parliament entitled ‘for improving and completing the Navigation of the Rivers Thames and Isis from the City of London to the Town of Cricklade’.
The inaugural meeting on 9 May 1771 was held at the Town Hall, Henley on Thames. As before, the Commissioners were all local landowners and not necessarily impartial when it came to protecting their own interests. For balance, representatives from the riparian clergy and the mayors along the route were also appointed: the whole body numbered over 600 though rarely were more than a handful present.

Now began work to remould the Thames as a Georgian high-speed transport link. The Commissioners purchased the old flash locks and, in their place, built new pounds. The first of these completed was at Boulter’s Lock, just north of Maidenhead, which was the Act’s prescribed limit of building jurisdiction.
Between 1771 and 1778 a total of ten new pound locks were built, stretching upstream from Boulter’s to Mapledurham, just west of Reading. One of these was at Marlow, which was finished in 1773. Each pound removed approximately half a day’s travel for the barge crews.

William Havell print published in 1818 entitled The Weir, From Marlow Bridge. This was part of a series of engravings entitled Picturesque views of the River Thames, commissioned by the Thames Navigation Commission to demonstrate the improvements they had made along the river (reproduced with permission of Reading Museum)
Although the Commissioners invested large sums in lock construction, it was not long before the timbers needed replacement or further improvements were identified. Marlow was such a case in point. In 1825 a new cut was made and a new pound lock built, with the old pound being filled in.

The detail of this work is contained in the accounts of John Treacher II, a carpenter from Sonning, who succeeded his father in 1802 as General Engineer to the Navigation. Treacher records the stages of work at Marlow: ‘Digging out the Ground at the New Pound’, ‘Pumping out Water and Getting stone from the Wharf to the Pound’, as well as his bill for ‘Beer for the men working at the New Pound’.
Account of the building of Marlow Pound Lock,1825-1826, D/EX1457/1/16


To illustrate the scope of the Commission’s work, one of Treacher’s colleagues, Zachary Allnutt of Henley, compiled this volume of ink and watercolour plans in 1815. A working document, annotated with subsequent changes to the Commission’s property, it details the pound locks of the upper navigation at a time when they had made the river safely and quickly navigable to traffic from Runnymede to Lechlade.
Plans of the pound locks and lands belonging to the Commissioners of the Thames Navigation, drawn 1809-1882, D/TC/J1/7/8
Once the new pound locks were ready, rules and regulations had to be drawn up for the staff employed to operate them and for the river traffic filtering through. This notice details those rules as well as the penalty to be incurred by anyone who was found to contravene them. For the first time, traders had consistency along the route.

In return, the locks generated vital income for the Commissioners, allowing them to fund further improvements to the Navigation. The Thames barges carried a vast array of goods up and downstream and every stop at every lock incurred a toll.
This list of barges is another production by Zachary Allnutt, made in 1812. The list gives the number, name and tonnage of each barge, and the name and place of residence of its owner.
Tolls were levied against barges and calculated per ton, with trade recorded by the Commissioners and provided as evidence to justify the extensive works required and money sought via loans borrowed under the Acts.
Evidence and Report to Parliament by Robert Mylne, surveyor, on Improvement of the Thames and Isis also the Grand Junction Canal Act 1793, including information on the current state of the river, D/TC/J1/4/1
The Commission was deliberately stopped from encroaching on the rights of the City of London. The latter maintained the tidal Thames but also the last miles of the upper river. To match the Commissioners’ improvements, the City was obliged to fund its own pound locks between Staines and Teddington, requiring a separate Act of Parliament for each that it wished to build. In return, it could collect its own tolls.
Plans of proposed new pound locks at Penton Hook and Molesey by the Corporation of London, 1814, D/TC/J1/8/8 and D/TC/J1/8/9
However, neither the City nor the Commissioners were immune to competition from other trade routes. Recognising the threat, the Commissioners successfully fought a proposal to build the Berks and Hants Canal but were unable to defeat the construction of the Great Western Railway. Although they succeeded in having the first Railway Bill defeated in Parliament, the GWR was incorporated in 1835.

The railway’s opening in 1838 spelt disaster for the Commission. Over the next twenty years the GWR gradually acquired more and more of the river’s trade. At the same time, many of the Georgian pound locks were falling into disrepair and there was no money to fix them.
In 1857, the Thames Conservancy was created to manage the tidal river and the City’s various interests in the lower locks. In 1866, facing bankruptcy, and after a highly-critical report on their maintenance of the river, the Commission was abolished. Its property was transferred to the new Conservancy instead and, for some forty years, the whole of the tidal and non-tidal river was under the control of one master. Immediately, the new and solvent Conservancy began a programme of lock repairs to replace the original timbers and other features. New locks were also built between existing ones, such as those at Romney, Hambledon and Benson.

Money continued to be a problem. In 1878 a further Act provided for additional payments to be made by the London water companies who were now permitted to take water from the river. This allowed a further period of repair and building, with new pounds at Grafton, Northmoor and Shifford, and a new weir at Eaton.
The Conservators’ jurisdiction over the whole river came to an abrupt end in 1909. The growth of the London docks, coupled with the myriad different interests attempting to develop or regulate them, led Parliament to believe they would be better managed by one central authority. So it was that the Port of London was created and subsumed the Conservancy powers for the river below Teddington.
Between then and the Second World War, much of the Conservancy’s efforts were diverted to land drainage. Vast areas around the Thames and its tributaries were engineered to become agricultural land, boosting the nation’s food production. By the end of the war, many of the river’s locks and weirs were once more in a state of disrepair.
The post-war period saw new investment in lock-keepers’ housing and in mechanising the pound lock gates. This was the last act of the Thames Conservancy before its era came to an end on 1 April 1974. It was abolished by the Water Act 1973, its powers were transferred to the new Thames Water Authority.
By then, the river had been transformed since the Commission built that first pound at Boulter’s Lock. Though now completely navigable, and used by more people than ever before, it was also no longer a major trade route. The highway’s legacy would be felt in other areas.