Enclosed in the rear of a copy of Berry Wiggins' 'Bitumen Coatings for Thermal Insulation' was the following letter.
"13th January, 1955
"To: Mr. R.G. Bruce, Laboratory.
"Berry Wiggins - "Bitumen Coatings for Thermal Insulation"
"This book is well written and contains much practical advice.
"Of Berry Wiggins' list of products, we have only examined three - "Tensulac" (Primer Grade) 5258 and "Aquaseal" 5 and 1081. We have also examined "Tensulac" KA4116. The "Tensulacs" resemble "AQUATEX" Solution, but are more fluid - they are solutions of Bitumen in Coal Tar Naphtha. "Aquaseal" 5 resembles our Standared Clay Bitumen Emulsion, while our No. 7 Clay/Bitumen Emulsion was based on "Aquaseal" 1081. Kingsnorth 835 appears to be 60/70 Pen Bitumen, Kingsnorth 1116 and 1122 appear to be Oxidised Bitumens."
The letter appears to be the result of some reverse engineering being conducted by one of Berry Wiggins competitors. Berry Wiggins & Co. Ltd was based in London, had laboratories in Stratford, and refinieries and works in Kingsnorth, Kent; Weaste, Lancashire; Ellesmere Port, Cheshire; and, Alloa, Scotland. In 1964, it was one of only eight firms refining oil in the UK, having an annual capacity of 190k tons (the others, BP, Esso, Shell, Mobil, Texaco, Phillips-Imperial and Burmah, would each go on to become giants of the modern petrochemicals industry.) A footnote to the Monopolies and Mergers Commission Report on Petrol of 1979 mentions that Berry Wiggins had ceased oil refinery by 1977.