ICI opened their ‘Oil Works’ at Billingham in 1935 with a visit from Ramsay MacDonald, former Prime Minister and new Lord President of the Council. The ‘Oil Works’ were built to provide a secure supply of petrol from coal for the United Kingdom, free from the ranges of any future submarine war. New engineering skills were developed to contain the high pressures and temperatures needed and new standards of safety were established to cope with the hazardous gases. As technology changed the plant grew and developed, eventually though further growth was no longer possible and decline was inevitable. The plant finally closed in February 1994. 
Picture Stockton Archive
A Pictorial History of Stockton-on-Tees
Aviation fuel was made from Creosote at the coal oil plant in Billingham. When all the dye works came together in 1926 with the formation of ICI, known to us as the Synthetic, it was mainly for dyes made from coal. Then it was to produce high octane fuels during the war. Later it became the Phenol and Alcohol making plant. The new Oil Plant at North Tees produced Cyclohexane, benzene, Toluene, Xylene and Petrol with other light oils. The old plant at Billingham was not a favourite for the maintenance crews, if you got it on your clothes they could smell you coming a mile away. It makes one wonder, if the oil becomes scarce will we then go back to the millions of tons of coal waiting for development under our feet. The problem would be the high quantity of Hydrogen required to make fuel from the coal. I can see the time when the economics bring back the use of coal as China uses it for growth now, so we will need to at some future date.
I believe that the plant was eventually just used for hydrogenating coal tar and coal oils. These were more reactive than coal itself and prduced less wear.I also have a suspicion that the fuel produced would have been of the high octane type, especially valuable in high output aircraft engines. Can anyone confirm this?
Ramsay Macdonald is on the left, next to him is Lord McGowan, chairman of ICI 1930-1950. He was the second chairman of the company, and as Sir Harry McGowan, chairmen of one of the founding 4 chemical companies that formed ICI in 1926.