That is a great question, Sk1n1m1n. As someone who is neither a UK citizen nor lives within the UK, I am a very ardent advocate for cannabis legalization in the UK.
Just kidding. I live in the US, in the State of Iowa, medical cannabis is legal here for 11 qualifying conditions. Process starts by printing off a form from the Iowa Department of Public Health, taking it to your primary care physician, and they sign it, certifying you have one or more of the 11 conditions. Send it in to IDPH, they review it, say yes or no, you go to your local Department of Transportation with that info, they take your photo and print out a laminated card identifying you as a medical cannabis patient. The whole process can cost between $20-$200 roughly, and that's before you ever have your sights on a legal cannabis product. Legislators also put a max cap of 3 percent THC content on any medical cannabis product, and those in the know state a minimum of 10-13 percent THC content is necessary for significant medical benefits for the majority of the 11 qualifying conditions. Also, legislators allowed for 5 potential cannabis dispensaries to be built or operated over the entire state...and on and on.