The Six Nations and Sanzaar are facing another battle with World Rugby over a desire from some unions to ensure that none of them can be relegated from the Nations Championship .

As reported last week by the Guardian, the 10 leading unions have set up a new company, F10, to run the Nations Championship and sell their broadcast and commercial rights for all competitions other than the World Cup, which remains the property of the global governing body, World Rugby.

The creation of F10 has led to concerns elsewhere in the sport that some of the 10 founding unions, particularly Wales and Italy, want to introduce safeguards protecting them from relegation to the second‑tier Nations Cup, which is run by World Rugby .

In another potential flashpoint there is a desire from the smaller unions, shared by World Rugby, for the Nations Cup commercial rights to be bundled with and sold alongside those of the Nations Championship, which would give them a right to a share of the proceeds.

While the Nations Championship…