Which of the following countries is well known for having an uncodified or unwritten constitution rather than a single written document?

Introduction / Context:
Comparative constitutional questions often highlight differences between countries with written constitutions and those with uncodified or unwritten systems. India, the United States and many other countries have a single written constitutional document. However, some countries follow a system where constitutional rules are spread over statutes, conventions and judicial decisions without being consolidated into one formal text. This question asks which among the listed countries is known for such an uncodified constitution.

Given Data / Assumptions:

The options list the United Kingdom, United States of America, India and Pakistan.
The question is about whether a country has an uncodified or unwritten constitution.
It is assumed that the learner knows the basic nature of the Indian and United States constitutions as written documents.
No calculations are necessary; only conceptual understanding is required.

Concept / Approach:
The United Kingdom is famous for its uncodified constitution. Its constitutional provisions are scattered across statutes like the Bill of Rights, conventions, judicial decisions and documents such as Magna Carta. In contrast, the United States, India and Pakistan all have written constitutions adopted at particular points in time. Thus, when asked which country has an unwritten constitution, exam candidates should immediately think of the United Kingdom among commonly mentioned examples.

Step-by-Step Solution:
Step 1: Recall that India has a long written constitution adopted in 1949 and in force since 1950. Step 2: Recall that the United States has a written constitution adopted in 1787 and effective from 1789. Step 3: Recognise that Pakistan also has written constitutional texts, including the constitution currently in force. Step 4: Recall that the United Kingdom does not have a single written constitution; instead, constitutional rules exist across statutes, conventions and judicial precedents. Step 5: Based on this comparison, identify the United Kingdom as the country with an uncodified or unwritten constitution.

Verification / Alternative check:
Verification can be done by consulting introductory texts on political science or comparative constitutional law, which usually use the United Kingdom as the classic example of an unwritten constitution. They contrast it with codified systems such as those of India and the United States. Examination notes often highlight this contrast because it helps students understand the nature of the Indian Constitution as a single written document derived from multiple sources, unlike the British system. This consistent explanation across books confirms the answer.

Why Other Options Are Wrong:
United States of America: Has a written constitution consisting of the original seven articles plus amendments, clearly codified in one main document.
India: Possesses a detailed written constitution adopted by the Constituent Assembly, which is among the lengthiest in the world.
Pakistan: Has written constitutions adopted at different times, including the one currently in force, and is not an example of an uncodified system.

Common Pitfalls:
Some learners may misinterpret the term unwritten and assume it means the absence of any legal basis, which is not correct. An unwritten constitution is still based on laws and conventions; it is simply not codified in a single text. Another pitfall is to be misled by the age and global influence of the United States Constitution and incorrectly label it as unwritten in a figurative sense. To avoid these errors, students should clearly remember that, among the commonly tested countries, the United Kingdom is the standard example of an uncodified constitution.

Final Answer:
The country well known for having an uncodified or unwritten constitution is the United Kingdom.