What are the good private health insurance companies in the UK?

Having experienced the slowness of NHS and the expenses of the private in the UK, I am thinking of buying a private insurance policy to save myself. Anybody has good recommendations?

If you dont have a pre existing condition natinational friendly

Whichever one you choose make sure you read the small print carefully. Some have multiple exclusions and you need to be aware of this, especially pre existing conditions and lifestyles, which you must be honest about or it invalidates the insurance. Some have tiered levels of healthcare so dont pick the cheapest and then expect total cover.
You can get quotes online so try a few and see what they come up with.

Thanks a lot for your advice. I am going to study the small print carefully

Another Question is that how do the insurance companies evaluate the existing condition ?do they go through GP’s medical records or do they base on the oral statement by the person himself on the phone?