The Competition Commission (CC) said a proposed joint venture between Anglo American and Lafarge in Britain could damage competition for construction materials in some markets.

Having struggled for more than three years to find a buyer for its Tarmac UK unit, which it bought as part of the larger Tarmac group in 2000, Anglo last year agreed to merge Tarmac UK with Lafarge's own UK cement, aggregates, concrete and asphalt businesses in a 50:50 joint venture.

However, the CC on Tuesday said the venture could lead to a substantial lessening of competition for the supply of materials including bulk cement, rail ballast and asphalt in certain markets.

The CC said it was now consulting on the possible actions it could take in response.

It said it would publish a list of possible remedies, outlining the way that anti-competitive effects of the joint venture could be prevented, and would accept comments by March 13.

(Reporting by Rhys Jones; editing by Paul Sandle)