Subsequently, the company expanded overseas, predominantly into commonwealth countries and South and Central America.

The initial prospectus of the merger[3] (in a time before anti-trust laws) was to unify the entire British cement industry, eliminating competition, and excluding imports.

In 1911, a second attempt was made to unify the industry: 33 companies, including all the original drop-outs, were merged to form the British Portland Cement Manufacturers Ltd.

Similar deals were made for plants in Vancouver Island, Canada and the Orange Free State, South Africa in the same year.

At various times, the company owned or part-owned manufacturing capacity in Australia, New Zealand, Malaysia, Indonesia, the Philippines, India, Nigeria, Zimbabwe, Kenya, Tanzania, Egypt, Ireland, Spain, Denmark, Greece, United States, Chile and Brazil.

The company gradually built up a competence in the technical aspects of low-cost cement manufacture, and installed many new plants during the period 1950–1970, to its own specifications.

The company's UK capacity reached its peak of 13 million tonnes per annum in 1973, and ultimately fell to half that level.

The Office of Fair Trading referred the deal to the Competition Commission, which instructed the two companies to sell off the Hope works in Derbyshire along with over half of their proposed joint UK ready-mix concrete capacity, together with sundry other facilities including asphalt plants, as a condition of approval for the joint venture.

This led to the creation of Hope Construction Materials, which commenced operations in 2013 as Britain's leading independent producer of cement, ready-mix and aggregates, following acquisition of over 170 operational sites, including the former Blue Circle Hope cement works.

In 2015, following the merger of Lafarge and Holcim, as part of another complex deal to appease European competition regulators, the Irish building materials company CRH plc took control of a number of former LarargeHolcim assets, including the Tarmac and Blue Circle brands, together with the former Blue Circle works locations of Aberthaw, Barnstone, Dunbar, Northfleet and Westbury.