What is the name of the UK official responsible for defending the realm?

The UK official responsible for defending the realm is the Minister of Defence. This position is crucial in overseeing the armed forces and ensuring national security. The Minister of Defence leads the Ministry of Defence and is tasked with formulating defense policies and strategies, managing military operations, and liaising with allied nations. This role is essential for maintaining the safety and security of the country against external threats.

In contrast, the Secretary of State for Health focuses on public health and social care, while the Home Secretary is responsible for internal affairs such as immigration, policing, and national security related to law enforcement. The Chancellor of the Exchequer manages the economic and financial matters of the UK, overseeing the Treasury. Each of these roles plays a vital part in the government, but when it comes to defending the realm, the responsibilities squarely fall on the Minister of Defence.