The law society recommend pay rates for trainees. Any solicitor whom you do not know personally (relative or the like) who employs you without paying, is, in my view, not someone that you should be learning from. There are enough rotten eggs in the profession without creating more. If there is no work for trainees that is worth paying for then there sure as hell is no work for them when they qualify. Do the people who want to be trained without pay want to continue working as solicitors without being paid? Where does this leave the client? Would you be happy having someone handling your personal affairs and possibly a lot of your money who is not being paid?
I was paid very little as a trainee in the 90's and got very poor legal training but learned a lot about how offices work (and can type very fast!). Luckily my first post qualification job was with someone who was interested in training and it was on the upward curve of the boom so there was lots of work to do. It's a bit like doctors, if you do not get enough practical experience you cannot do the job, this is true for trainees and solicitors. A lot of solicitors are quite underemployed at the minute and will be having trouble keeping their knowledge up to date. Solicitors are not hiring trainees because they don't have anything for them to do, they barely have enough to do themselves. I would have thought that having a smart, underemployed, unpaid person hanging around your office would be a huge liability.
Anybody looking for an apprenticeship should concentrate on the litigation firms and the long established with good reputations. There is always more lititgation in a downturn. I have moved from doing 70% non contentious two years ago to mainly contentious now, If things continue the way they have being going since the beginning of the year I would see jobs becomming available again towards the end of the year, but on the litigation side.