Academies, trust schools, league tables and national testing - all controversial issues that dominate the education debate in England but which simply do not exist in Wales.
Now teachers' pay could be about to join them in highlighting the growing differences in school systems on either side of Offa's Dyke.
Alan Johnson, the Education Secretary, has asked the School Teachers'
Review Body to consider whether there should be a "more flexible approach", allowing separate decisions about teachers' pay in Wales.
The current situation is on the face of it, straightforward.
Responsibility for teachers' pay has not been devolved to the Welsh Assembly. Teachers in both countries have the same structure and salary levels, decided in Westminster. But independence over certain issues, such as performance management and staff restructuring, which affect pay, has been jealously guarded by the Welsh Assembly government.
Combined with a different approach to funding the upper pay scale, this means there has already been some potential for variation in pay according to whether teachers work in England or Wales. The point was noted by the review body as long ago as November 2003. Now it seems Mr Johnson is pushing for the disparity to be resolved.
UCAC, the union for Welsh-speaking teachers, is "over the moon" about the prospect of power over pay going to the Assembly.
Gruff Hughes, general secretary, said: "As a union we were set up to fight for an education system separate from England and this would be the completion of our aims. I think there has been a lot of scaremongering that teachers' pay would go down if pay and conditions were devolved." For the other unions, though, the idea of a more "flexible approach" for Wales conjures up the spectre of regionalised pay that the Government has pushed for in previous years. They believe a more localised system would mean some members losing out.
David Evans, the National Union of Teachers' Wales secretary, said:
"Because Wales is a small economy with a lower average wage, the big fear is this would mean a drop in wages, with an exodus of better teachers over the border."
Mary Bousted, general secretary of the Association of Teachers and Lecturers, believes that in the long run teachers outside Wales could also suffer.
"There is always the danger of a domino effect, with lower pay spreading to some areas of England," she said. But like Chris Keates, her NASUWT counterpart, she believes it is Cardiff rather than Westminster that is to blame for pushing the issue back on to the agenda.
"The constant desire by the Welsh Assembly to do things differently, although not necessarily better, with regards to pay and conditions has generated increasing difficulty, tension and frustration," said Ms Keates.
"The review body has commented on this previously and the Secretary of State has little choice but to raise the matter for consideration."
Teachers in Wales fear giving the principality extra flexibility over pay would inevitably lead to Welsh salaries falling behind.
Anna Spokes, who works at Archbishop Rowan Williams Church in Wales school in Caldicot, Monmouthshire, said: "Schools in Wales have funding problems and it is due to get worse. If we had our own award, the pressure would be to hold down pay."
The Welsh Assembly government denies any desire for power over teachers'
A spokeswoman for Jane Davidson, its education minister, said she never acted without consulting the views of people in Wales and had detected no appetite for acquiring the responsibility.
Nevertheless, the Government of Wales Bill currently passing through Westminster could soon make it easier for such a transfer of powers to take place. When it becomes law, there is likely to be pressure from devolutionists to grant the assembly more powers and some suspect that Mr Johnson is acting now so that the issue of teachers' pay can be settled in advance.
A Department for Education and Skills spokesman would only say: "This is a sensible review of existing arrangements, and is not a precursor to devolved pay arrangements."
But Ms Bousted said: "It was inevitable this was coming and if the Welsh Assembly government doesn't want it, then it had better start doing a lot more to implement national pay and conditions."
* Mark Langhammer, Association of Teachers and Lecturers' director in Northern Ireland, wants the province brought under the STRB system to restore parity with England and Wales."Teachers should be paid the same for what they do whether they work in Belfast, Barry or Bradford," he said.
Teachers' pay and conditions have not been devolved to the Welsh Assembly and so in theory are the same as for English teachers outside London.
But guidance is devolved to some extent on issues not relating directly to pay, such as performance management, continuous professional development and staff restructuring.
This has led to some minor variations. For example, the deadline for schools to draw up new staffing structures, and introduce teaching and learning responsibility payments, was three months later in Wales than in England.
The fact that school budgets are set separately in Cardiff and Westminster can also lead to differences in pay.
The Welsh Assembly government proposed not to set cash limits when funding upper pay-scale progression, for instance, and there are no advanced skills teachers in Wales because the Assembly government decided against funding them.