 As with so many companies in the construction industry, the Second World War increased the demand for Tarmac’s services, notably for surfacing the large numbers of airfields being built or modernised.By the time of its half centenary in 1953, Tarmac was processing over two million tons of slag a year, its road surfacing had developed into a significant civil engineering business, and its Vinculum subsidiary "had become one of the major precast concrete undertakings in the country.