who can diagnose?

I've tried searching for the answer on google, but I can't seem to find anything definite on any professional/government websites. Most of the websites that do come up are from the USA and about their policy. I know in the UK, a psychiatrist can make a diagnosis. But I am curious whether clinical psychologists can make a diagnosis? This seems to vary from country to country. The clinical psychologists in the UK seem to also range in a variety of degrees, such as PhD, PsychD, ClinPsychD, DClinPsy... are they different in any what they are allowed to do?