Visa Requirement for Blue Card Holder To Go To UK

Hi to everyone. I have a question which many people have no idea about.

I want to write down the inputs as items to make it clear;

- I am holding a Turkish passport (non-EU country)
- I am living and working in Italy (Blue Card holder)
- I need to go to UK (non-EU country but Turkish citizens have to apply for a visa)

So i can generalize my question like this:

Must a non-EU country citizen apply for a visa to go to UK even if he/she has Blue Card in a EU country?

Thank you very much in advance.

Cem