Good day Awesome people!,
I am asking on behalf of my sister in law for advise on British Protected Person by descent.
She was born in Salisbury, Rhodesia in 1972.
Her father was a BPP of Tanzanyika, he was born there in 22 September 1938 (he had a British Passport stating British Protected Person). Killed in Rhodesia soon after she was born.
His father was born in Tanzania 14 July 1911 (Passport: British South African). His mother was born in Kenya 1 July 1916 (Passport: British South African).
Can she claim BPP by descent?

Does she hold any other nationality? What was/is the nationality of her mother?

She became a South African citizen, I assume when her mother became one.
Her mother (deceased) was born in Salisbury, Rhodesia 11 May 1943. (became citizen of South Africa in 14 January 1981).Widowed 18 November 1979.
Her mother's mother (deceased) was born in Salisbury, Rhodesia 24 September 1920.
Her mother's father (deceased) was born in 24 January 1912 in South Africa.

Hi BIP
Is her mothers route a possibility?

It's unlikely given that she would have needed to have always been stateless.

I would have assumed her grandmother and mother had been British Subjects born in Salisbury Rhodesia...1920 and 1943 based on
PART I - British Nationality 1948
1 British nationality by virtue of citizenship
(1) Every person who under this Act is a citizen of the United Kingdom and Colonies or who under any enactment for the time being in force in any country mentioned in subsection (3) of this section is a citizen of that country shall by virtue of that citizenship have the status of a British subject.
(2)Any person having the status aforesaid may be known either as a British subject or as a Commonwealth citizen ; and accordingly in this Act and in any other enactment or instrument whatever, whether passed, or made before or after the commencement of this Act, the expression " British subject " and the expression " Commonwealth citizen" shall have the same meaning.
(3) The following are the countries hereinbefore referred to, that is to say, Canada, Australia, New Zealand, the Union of South Africa, Newfoundland, India, Pakistan, Southern Rhodesia and Ceylon.

Going back to her dad who was a British Protected Person born in Tanganyike, at the time of her birth - British Nationality Act 1948.
Part II Section 5 Section (1) Subject to the provisions of this section, a person born after the commencement of this Act shall be a citizen of the United Kingdom and Colonies by descent if his father is a citizen of the United Kingdom and Colonies at the time of the birth:
Provided that if the father of such a person is a citizen of the United Kingdom and Colonies by descent only, that person shall not be a citizen of the United Kingdom and Colonies by virtue of this section unless—
(a) that person is born or his father was born in a protectorate, protected state, mandated territory or trust territory or any place in a foreign country where by treaty, capitulation, grant, usage, sufferance, or other lawful means, His Majesty then has or had jurisdiction over British subjects ;
and
12 (3) A person who was a British subject immediately before the date of the commencement of this Act shall on that date become a citizen of the United Kingdom and Colonies if he was born within the territory comprised at the commencement of this Act in a protectorate, protected state or United Kingdom trust territory.