The Royal Photographic Society is at the forefront of promoting the art and science of photography in the UK and around the world. Membership is open to anyone associated with and interested in photography in any of its myriad forms and is well worth the small annual fee. The society also offers three levels of distinctions which are a great way of validating, both to yourself and others, your prowess and skill as a photographer. I became a member in 2013 and achieved the LRPS in January 2014, which was at once a throughly enjoyable yet also nerve-wracking process that ultimately only helps you grow as a photographer. I'd recommend looking into the RPS and joining as a member if you are keen on developing your photographic skills, or even if you just want to keep up with photographic events, courses and workshops/outings throughout the UK and beyond.
For more information just follow the link to their website.