Q:

What is the status of children of a person who is British by descent?

My son, born in Rome, is British by descent.
He has a newborn in China who he wants to register as British. He has been declined a passport for her as you cannot apparently pass on British citizenship to the child of one who is British by descent.
What is the status of his child?

A:

They're correct. British citizens by descent cannot automatically pass British citizenship to a child born abroad. There are limited circumstances in which such a child can be registered as a British citizen while under 18:

If your son's parent (the child's grandparent) was a British citizen otherwise than by descent, and your son lived in the UK for some continuous period of 3 years some time in his life before the child's birth, the child can be registered as a British citizen by descent under section 3(2).
If your son and his wife and his child have all been living in the UK for the last 3 years, the child can be registered as a British citizen otherwise than by descent under section 3(5).
Under special circumstances, the Home Secretary has the power to register any child under 18 as a British citizen under section 3(1). This is usually for children who are already in the UK and have strong connections to the UK.

A:

That's absolutely correct. If a person is British citizen by descent, then their children are British citizens not by descent if born in the UK, and not British citizens at all if born outside the UK. 
To become British citizen, your son would have to move to the UK with his child and reside there for a long time, then apply to get residency and citizenship like any non-British child might do.

A:

You may find this UK government webpage ("Check if you're a British citizen") useful to test your thoughts. It poses questions in order to determine British citizenship.
Better Answers contain actual text and substantive information, so the Answer remains useful if the link disappears. This issue's presentation on the UK website, however, has too many pages and conditions to easily quote or abstract.

