Final answer:
The question is asking about a highly acclaimed musical group in Great Britain that performs internationally. A string quartet fits the description as these groups often tour globally and receive widespread recognition.
Step-by-step explanation:
The question refers to a musical group from Great Britain that has achieved international fame and critical acclaim. Given the options, the most suitable answer would likely be a string quartet, as these groups are known for their classical music performances and often tour globally to high praise. A ukulele club is less likely to perform worldwide and receive such widespread recognition, a skiffle band had its peak popularity during the mid-20th century, and while a folk ensemble could potentially fit the criteria, it is not typically associated with the level of international touring and recognition described in the question.