A Parent Council advises the head teacher and governors. As the name suggests, they are made up of parents, but members may be selected from a parent forum. The Parent Council often has formal links with the PTA and the two bodies can both work to improve the school.
For best results, the parent council membership needs to reflect the entire school community and although this can be tricky to achieve, having representatives from every class or year group helps. Children of varying ages need support in different ways. Parent Councils are especially relevant in secondary schools where links between home and school are less immediate. A well-run forum can drastically improve home-school relationships by making the Head Teacher accountable to parents in a very real sense.
More about parent councils.