Many thousands of people have been responsible for the upkeep of the river over the last 250 years. Headed by the Commissioners and Conservators and those based at the London (and later Reading) headquarters the physical work of managing the river was undertaken by engineers, inspectors, labourers, and lock, weir and ferry staff.
Here are a few of the people who have helped care for the river:
The Conservators
The Conservancy was governed by a board of Conservators: individuals selected to represent what were considered to be the vested interests in the river. Initially, there were only 12 Conservators, who represented the Corporation of London and the Government. In 1864 this expanded to 18, and representation opened up to the merchants, ship and dock owners in London. When the Navigation Commission joined in 1866, it was granted only four Conservators on the board, to be elected from amongst the Commissioners.
Conservator membership was made more equitable by the Conservancy Act 1894. This limited terms to three years, fixed the number at 38 and allotted additional places across the local councils along the river. In 1909, the London and business membership was lost to the new Port of London and the board remained thereafter appointed only by Whitehall and local councils.
William Grenfell, 1st Baron Desborough, Chairman, 1904-1937
One of the longest serving and most influential Chairmen, Grenfell was an accomplished sportsman who had represented Britain at fencing and rowed for Oxford. He also won the Upper Thames Punting Championships for three years in a row from 1888 to 1890. He was both a Liberal and a Conservative MP, living in Taplow Court, he supported various local causes in his adopted town of Maidenhead.

One of the most important undertakings during Grenfell’s Chairmanship was the creation of an artificial channel to straighten the river between Shepperton and Walton Bridge and to improve flow rates down river. At the same time a new island was created between the original and new streams. Grenfill opened the cut in 1935 and they were named Desborough Cut and Island in his honour.
Helen Bentwich
During the Thames Conservancy there were three women who served as Conservators, all during the 1940s-1960s. The first in April 1946 was Mrs M M Ashdown, who was a Labour councillor and represented Middlesex County Council. She joined the Board for three years until 1949, followed by a further six-year stint from 1955. During her absence Mrs Helen Bentwich, representing London County Council, was appointed in November 1952. She was joined in November 1961, by Mrs W D de Pass, representing Oxfordshire County Council. They both retired from the Board in April 1965.

Born in Notting Hill, and with close connections to Palestine, Mrs Bentwich was active in helping children escape Nazi persecution before she became a London County Councillor in 1937. She was elected Chairman of the Council from 1956 to 1957 and served until the authority’s abolition in 1965. In the same year she was appointed CBE.
Surveyors and engineers
The people who shaped the river the most over the years were the surveyors and engineers who surveyed, planned and designed all of the locks, weirs, new cuts and general improvements to the river. Along the way they created hundreds of plans, many several metres long, which record all the changes that have taken place.
The Treacher family
For nearly one hundred years, the Treachers of Sonning dominated lock-building on the Thames. John senior (1736-1802) was a carpenter who began work for the Navigation Commission in 1773. In 1791 he was appointed surveyor for the upper reach and from 1795 he was General Engineer across the whole Navigation. Most of the pound locks were originally made under his direction. After his death he was succeeded by his son, John (1760-1835), who was titled General Surveyor of the Commission from 1821. His son George (1791-1863) also succeeded his father until he resigned through ill-health in 1862.
![Extract from accounts reads, ‘1791 Novemb[e]r The Gentlemen Commissioners of the Thames Navigation to John Treacher for work he has Paid for Doon Between Mapledurham and Nuneham Lock. from the 5th of Novemb[e]r 1791 to the 24 of March 1792’.](https://thames250.files.wordpress.com/2021/05/d-ex1457-1-1-001-treacher-close-up-1.jpg?w=1024)
George’s grandson later wrote that:
‘the family held tight to the Commission throughout its existence. Frankly it was disastrous to them.’
The Treachers subsequently ran a market-garden in Twyford.
Robert John Courtenay Mostyn
Robert Mostyn was one of a new kind of highly trained and skilled engineers who worked on the Thames. Born in Ireland in 1846, he began a four-year pupillage at the age of 21 in the company of Messrs C D Young & Co, engineers and millwrights, in Perth, Scotland. Here he learnt the tools of his trade, spending time in the various shops and drawing office. Once his training was complete, he joined the firm of Mr R M Oldish preparing drawings of bridges and other structures. He then spent several years in private practice before being employed by the Thames Conservancy in 1883 to work on the preparation of designs for new works on the river. Projects that he worked on include a survey of Cutler’s Eyot in Windsor.
In 1884 the Conservancy’s senior engineer Charles J More, successfully recommended Mostyn for Associate Membership of the Institute of Civil Engineers. After two decades working for the Conservancy he died in September 1908.
The Lock-keepers
Lock-keepers were expected to serve river users at all hours of the day. Early lock staff were faced with heavy manual work, harsh conditions in winter with little pay and only a basic standard of living, although they were housed. The Conservancy received regular petitions for improved pay and conditions and lock-keeping staff were eventually represented on the board’s committees.
Edward Light, Sonning Lock-keeper
Edward Ernest Light joined the Thames Conservancy is his early twenties, starting off as an assistant at Teddington Lock, before being promoted to lock-keeper at Culham in 1907 and then at Sonning in 1912, at which point his weekly wage increased from 15 to 16 shillings. He enlisted in August 1914 and served in the Royal Navy for nine months. Injured on duty, he returned to duty at Sonning Lock.
He remained in post for the next three decades and became well-known for his immaculately kept lock garden. Throughout the 1930s he competed for the Sir Reginald Hanson Challenge Cup for best-kept lock garden. The main competition came from Teddington Lock and the two locks won the cup on alternating years throughout the decade. One Sonning resident was so aggrieved that Teddington had beaten Sonning in 1934 that he wrote to Lord Desborough.
In answer to the letter the Committee wrote:
‘The Committee experienced the greatest difficulty in deciding between the gardens at Sonning and Teddington … Both gardens had been brought to a high state of perfection although so vastly different in type and it was only after very full consideration that the Committee decided to award the Cup to Teddington’.
In the 1930s Light was also active in promoting better wages and conditions for lock-keepers and was part of a deputation that presented a petition to the Lock Staff Special Committee in November 1938. During this he spoke about lock-keepers’ wives providing tea and refreshments.
