Mr Clarke admits he is "a little daunted" by the task ahead

Mr Clarke was selected after interviews with a panel which included 17 young people.

The appointment of the "children's champion" was the key recommendation of the Waterhouse Report into abuse at children's homes in north Wales.

In a statement to the Assembly, First Minister Rhodri Morgan said the appointment was a milestone.

"The successful establishment of the commissioner's office is a major achievement and a first for Wales in the UK," said Mr Morgan.

"Wales can truly be said to have a champion who will safeguard and promote the interests of its children and young people."

Mr Clarke said he was a little daunted by the task ahead.

Support from children

" I can move forward with confidence that I have got the support of all the parties in the Assembly, the support of a large number of adults in Wales, the support of all the charities and children's organisations," he said.

"Most importantly I have the support of the children who selected me.

"Initially there are going to be a lot of things to do just to set up the commissioner's office.

The post was originally attached to the Care Standards Bill, which meant only children in care could be covered by the commissioner but the National Assembly successfully pushed for wider powers.

Welsh Secretary Paul Murphy said Government legislation to extend the functions of the commissioner would be published shortly.

The Bill is expected to expand the commissioner's role by applying his powers to review and monitor arrangements for complaints, whistle-blowing and advocacy on behalf of children to a wider range of bodies.

These would include schools and NHS hospitals which provide services for children in Wales.