To transmit on amateur bands one must have a license. A license is acquired by taking a course and passing an exam. In the UK, currently it is necessary to first take a Foundation exam (one can then apply for a foundation, or M3 call). Next one must take an Intermediate exam (one can then apply for an intermediate, or 2E0 call). Finally one can take the Advanced course, and exam, and get a full M0 call.
Just because one has only an M3 call does not mean they have any less interest, or are any less qualified to be a part of an amateur community.