I have been a member of the Guild of Photographers for a few years now. They are a really friendly bunch of people and if you are intersted in photography as a professional or ametuer I would recommend you joining. I recently gained my Master Craftsman Qualification with the Guild which I am very proud of.
There are regional meetings held which provide a great way for photographers to meet up. You dont need to be a professional, you just need to enjoy photography.
There are yearly seminars where you can attend workshops on a variety of subjects.
They provide a mentoring service, where you can get advice from one of the panel members from just improving your photography to help with working for qualifications or competition entries. There is a fee for this but it is worth every penny. I would recommend it to anyone.
They also produce a colourful and informative magazine. I have attached a version here has some of the images on from the panel I submitted and gained my Craftsman qualification with last year. Pages 3 (botton right image) & pages 94-95
Full magazine here.