Prince Andrew And Price Harry Can Fill In For The King. Read How

The monarch, being the head of state of 15 countries, is also required to travel overseas. And, as monarchs are human beings, they may fall ill from time to time. So what happens when the monarch is required to fulfil constitutional duties, but cannot do so in person?

A fundamental principle at the heart of the UK constitution is that the crown never dies. On the death of one monarch, the heir to the throne immediately accedes. This smooth transition ensures that the government (which is carried on in the name of the crown) continues largely unaffected.

While the monarch is required to remain out of party politics, there are a number of decisions made by the government and parliament that require the monarch's formal approval. The appointment of a new prime minister, granting royal assent to new legislation and ratifying international treaties are just a few. Some of these matters require the royal sign-manual – the sovereign's personal signature.

The monarch, being the head of state of 15 countries, is also required to travel overseas. And, as monarchs are human beings, they may fall ill from time to time. So what happens when the monarch is required to fulfil constitutional duties, but cannot do so in person?

Under the Regency Act 1937, which was updated in 1943 and 1953, the monarch can delegate their powers to counsellors of state, two of whom must act together and exercise the powers of the monarch on their behalf. The law provides that the counsellors of state are the spouse of the monarch and the first four in the line of succession who are of full age (over 21) and domiciled in the UK. The heir apparent becomes a counsellor of state from the age of 18.