Wales' children's commissioner has told MPs of the extent of his fears over the creation of a similar post in England.
Peter Clarke was appointed in 2000
Peter Clarke has explained how the new role could confuse and undermine his position.
He fears his English counterpart would not be so independent of government ministers and complicate his work by having power over non-devolved matters.
Issues relating to the probation service for example, would be dealt with by England.
Cross-examined by members of the Welsh Affairs Committee on Thursday, Peter Clarke outlined the scope of his powers and responsibilities.
The central nub of his work, he explained, was being entirely independent of ministers and not being instructed by them.
Two Acts of Parliament control the commissioner but he is independent from government.
This, he added, would not be the case with the proposed
Mr Clarke was the first children's commissioner appointed in the UK back in 2001.
Proposals for a similar post in England was outlined in a green paper in September last year in order to improve accountability between different agencies involved with children.
Initially, Mr Clarke welcomed the possibility of similar appointments around the UK but in March this year he said he feared the role in England could compromise his power to act on behalf of Welsh children on some key issues.
On Thursday, he also revealed to MPs that the European Network of Children's Ombudsmen were so alarmed about the powers and function of the new role they had written a formal letter of protest to the chair of parliament's human rights commissioner at Westminster.
Earlier, Welsh health minister Jane Hutt side-stepped questions over how the UK Government had ignored the views of the assembly government in framing the Children's Bill, which will create the commissioner's post.
Jane Hutt does not want a UK commissioner to have a Welsh office
Ms Hutt said her policy was that the Wales' commissioner should provide a "one-stop shop" for children's services in Wales, including matters which were not devolved.
It made "no sense" to expect children in Wales to deal with more than one commissioner at a time and told the committee the English post should not have an office in Wales.
But, she went on, it was for UK Minister for Children Margaret Hodge to explain the proposed powers of the UK commissioner.
Ms Hodge has been summoned to appear before the Welsh affairs committee on 4 May.
The children's commissioner post was created in Wales in the aftermath of a report by Sir Ronald Waterhouse into the abuse of children over a period of 20 years across north Wales.
The office was set up to responds to complaints from children and provides a platform for their concerns and those of their parents.
The commissioner also has statutory powers to gain information from authorities about children.