udying in Reading, and they had two children, Michael George and Alison Victoria.

Kettlewell was a member of the King's African Rifles Reserve of Officers in Nyasaland, 1938-1939. During World War Two he served with the 1/2nd Battalion, King's African Rifles in British Somaliland, Ethiopia and Kenya against Italian forces until 1942. During 1942, his battalion was transferred to Ceylon with the 21st East Africa Brigade, part of the 1st (African) Division, and he served there in 1942 and 1943.

Later career
After his war service, Kettlewell returned to the Nyasaland Agricultural Department, occupying several senior posts, from 1943 to 1950. At this point in his  career, further promotion would normally have involved a move to another colony, to gain greater experience. He was offered a transfer to Uganda and a teaching post at the Imperial College of Tropical Agriculture in Trinidad. However, the Governor of Nyasaland, Sir Geoffrey Colby wished to retain his services and promoted him to be Deputy Director of Agriculture in 1950 so he could become Director of that department in 1951, and an ex officio member of the Legislative Council.

He was appointed as a Companion of the Order of St Michael and St George in 1955 in recognition of his services as Director of Agriculture for Nyasaland.

In addition to his membership of the Legislative Council, between 1957 and his retirement in 1962, Kettlewell served as a member of the Nyasaland Executive Council, which advised the governor. He was appointed Secretary, National Resources in 1960, and was described as "one of the most influential civil servants in the late colonial period" by the historian Kalinga. 

In the 1961 elections in which the Malawi Congress Party gained a majority of seats in the Legislative Council, a new Executive Council was formed in the expectation of a transition to independence. As Hastings Banda, the Congress leader wished to assume the important National Resources portfolio, Kettlewell became Minister of Lands and Surveys from 1961 to 1962. He