Is cannabis legal for medical use in the UK?

im doing an essay for english about something that is morally wrong and i think that medical cannabis being illegal is wrong as it can help so many people who are in pain, but then if it is legal it will be pretty embarrassing, and everything that i found on the internet about it doesn't give it a straight forward answer if it is or isnt. if it is legal, can anyone get it, is it difficult and can people go to prison for it and all that kind of stuff ?