The Associated Octel Northwich plant was the first site for the manufacture of Anti Knock Compound in the UK.

By the late 1930s TEL manufacturing plants had been built in Germany, France and Italy and by 1938 the British Air Ministry decided to proceed with plans to build their own plant. It was realised that without leaded petrol the British air force would be at a disadvantage as leaded fuel gave engines more power enabling aircraft to fly higher and longer. In fact it was known as “the magic bullet”.

A site at Holford Moss near Plumley, Northwich, Cheshire was chosen due to its relative remoteness and its proximity to a large wood which was seen as essential at camouflage. The site was also close to a railway and was already owned by ICI. Building work started in April 1939.

Associated Octel Northwich

Associated Octel Northwich 1939


Associated Octel Northwich 2015


The first charge of alloy was made at Northwich on 18th July 1940 and the first autoclave started on 9th September with Tetra Ethyl Lead (TEL) being produced a few days later.

NorthwichSite 001

Hu Fosset was sent from London office to be in charge at the Northwich works in April 1941. The site operated a 68 hour week over 7 days. Operators had 1 day off every 3 weeks. When not working at the site the operators had Home Guard duties and were often called upon to protect the site. The site at Northwich was very important for the war effort and was nicknamed’ “The Jam Factory” after one of the design engineers JM Jones.

During the war both Northwich and Hayle were owned by the Air Ministry but after the war they were purchased by “British Ethyl Corporation” which later became Octel.

Before the war leaded fuel was used mainly in air craft engines but by the end of the war more and more car engines were also using the fuel so expansion of capacity was required.Expansion meant finding new sites and Northwich was the centre for the design of new plants at Ellesemere port and Amlwch.Hu Fosset ensured that from 1945 onwards young engineers were trained in chemical plant operations at the Northwich. They became know as the “Woodden hut club” and from 1953 onwards engineers from Northwich moved out to plan and operate the other sites.

The nature of the chemicals being used and made at the Northwich site meant that the operators were required to undergo regular blood and urine tests for absorbed lead. In 1949 a medical laboratory was established at lostock green about a mile from the site.

In June 1961 work started on the production of TetraMethyl Lead (TML) as well as TEL.

The last charge at Northwich took place on 1st July 1985 and the plant was closed a few months later.