for most social work degrees, the universities now require you to have some experience of social care either paid or voluntary. There are now alot of private companies who take on people new to that area and train them ,especially helping them to get NVQ/SVQ. It is very difficult to train as a social worker within a local authority as places are very hard fought. Look in your local paper or on your local authority website.
General Social work council have a website that tells you where to train