A minister may announce a policy at breakfast, face hostile questions in the Commons at noon, find it challenged in court months later, and then see it altered in the Lords. That sequence is a useful starting point for any guide to British political institutions. British government is not one machine controlled from a single room. It is a set of old and newer bodies, held together by law, convention, party discipline and public consent.
For those who have dealt with government departments, trade missions or public authorities, the distinction matters. A decision that appears political can be constrained by the civil service, parliamentary procedure, the courts, local delivery or international obligations. The system can be slow and frustrating. That is partly its purpose.