Why is my Audi A1 producing a strange noise when I turn on the AC?

I recently noticed that whenever I turn on the air conditioning in my Audi A1, I hear a strange whirring noise coming from the engine. It's not very loud, but it's definitely noticeable. What could be causing this and is it a cause for concern?

The most likely reason for the noise is a worn-out AC compressor clutch. This is a common issue in older Audi A1 models, and it can be easily fixed by replacing the clutch.