If HRH Prince Henry's marry a Hrh Princess.And they live in her region as King and Queen.What happen's to Britian?

Britain would have to get itself a passport and physically move to that region where his wife was Queen of, simples.

Nothing happens to Britain.

Harry won't be king anywhere else as he has no claim.

Nothing. Harry is not likely to become King of the UK since he is currently fifth in line of succession and likely to go down the line as William, or eventually ,George and Charlotte, have children. Britain remains Britain and goes on as it does now.

Without Harry and his Apache helicopter Britain will be in big trouble.

Britain does not need Harry, or any of the royals, we would get along fine without them.

Nothing since his older brother William, and his nephew and niece are in front of him in succession to the throne in the UK. Only by some fluke, that if something happened to them, he would ascend to the throne.

Yes, in theory he might marry a queen regnant somewhere in the world;but he would not be king of her country, he would be a consort. aS He is well down now in the line of succession, it would have no affect on Britain

It would be as Queen and consort. The same as Queen Elizabeth and Price Phillip. It would have no effect on Britain or our royal family.

Nothing it would never happen.

William will be king of Britain, not Harry. so who harry marries won't affect that.

Nothing,the british monarchy has all the succession sorted, charles, william, george, george's children etc,if harry left britain it would make no difference at all

All hail King Charles and Queen Camilla.