The difference between the Foreign and Commonwealth Secretary and the Minister of State

Can anybody tell me the difference between the Foreign and Commonwealth Secretary and the Minister of State in the UK?
Are they all dealing with foreign affairs?

(sigh)

This has something to do with the Falklands War, doesn’t it?

Not really.
I just get confused with the two posts.

That’s because you’re interpreting Minister of State to be the same thing as the United States’ Secretary of State. They’re not the same office. In the United Kingdom, a Secretary of State may have one or more assistants known as Minister of State who is responsible to their secretary of state. In the United States, our cabinet officers are secretaries of their departments; for example, there is the Secretary of State who is responsible for, among other things, foreign affairs. In the United Kingdom, the secretary of state for foreign, Commonwealth and development affairs is responsible for:

Adding to the confusion, in some Commonwealth countries the Secretary is the senior permanent public (civil) servant of an Office of state, neither a minister or an appointed official (at least in the US appointing an outsider style) but most usually a career bureaucrat who runs the administration and ensures continuity of governance.

From Wikipedia that appears to be the case in India, Bangladesh and Pakistan and is also true in Australia.

Foreign Secretary (aka Secretary of State for Foreign and Commonwealth Affairs) is the boss of the Foreign and Commonwealth office - the equivalent of the US Secretary of State.

The Minister of State is a more minor role, unconnected to the Foreign Office. They represent the Cabinet Office (the department that supports the work of the PM and the government) in the House of Lords, and so are a peer rather than an MP. There are also (lowercase) ministers of state - basically all mid tier government ministers. Secretaries of State - known as the great offices of State - sit above them (these being the four people that head up foreign affairs, home affairs and the Chancellory (finance). Oh, and the PM of course).

Originally there was a single Secretary of State in England. The office developed from the post of the monarch’s private secretary; over time it came to be charged with general supervision of affairs of state not specifically the responsibility of, e.g., the Lord Chancellor, the Treasurer, etc. The duties became more and more onerous, and in the sixteenth century it became common to appoint two people to the office, so they could share the duties between them. Then over time a formal division of duties emerged. Initially the business of the office was divided into the Northern Department and the Southern Department. The Secretary of State for the Northern Department dealt with home affairs in the northern part of the kingdom and foreign relations with the states of northern and eastern Europe; the Secretary of State for the Southern Department dealt with the south of the kingdom and with the countries of southern and western europe, the Ottoman empire and the North American colonies.

In 1782 the business was redivided into home affairs and foreign affairs, and we have a Home Secretary and a Foreign Secretary. And then in the modern period the office is further divided, so we have a Secretary of State for Transport, a Secretary of State for Education, etc. Basically, most government departments are now headed by the Secretary of State for Whatever, with the exception of departments dealing with matters that were never under the Secretary of State to begin with — most notably the Treasury, headed by the Chancellor of the Exchequer.

Thank you all for your informative answers and explanations.