What are the statutory powers to make a compulsory purchase order?

The power to acquire land compulsorily can be found in a number of different statutes. https://www.gov.uk/guidance/compulsory-purchase-and-compensation-guide-1-procedure

When such a power exists, CPOs are made in accordance with the procedures contained in the Compulsory Purchase Act 1965, Acquisition of Land Act 1981, and Housing and Planning Act 2016.