He was born on 1 August 1900 at Little Blencow Farm near Greystoke in Cumberland the fourth child of Thomas Wannop (d.1930), a farmer, and his wife Esther Ann Robson.
In 1943 he joined a British Mission to the USA to exchange experience of farming issues with US farmers and in 1948 was appointed as Scientific Advisor to the Department of Agriculture for Scotland.
His proposers were Sir Patrick Laird, Stephen Watson, Edward Wyllie Fenton, and Alick Buchanan-Smith, Baron Balerno.
In 1957 Edwin Porter Arrowsmith asked the UK government to send a hill-farming advisor to the Falkland Islands.
They had three children including the urban and regional planner and author Professor Urlan Wannop, Ann and Ewen.