Having completed the three-year course at the Royal Agricultural College, Cirencester, Malcolm worked for a firm of land agents in Oxfordshire. That led him into commercial agency which involved working in London. In 1984 his career changed again when Mrs. Margaret Thatcher, the Prime Minister, invited him to join her reforming government. He started as a Whip and Lord in Waiting to The Queen before progressing to an Under Secretary of State at the Department of Transport and then Minister of State at, successively, the Home Office, Department of the Environment, the Treasury, the Foreign and Commonwealth Office and back to the Department of Transport. He is the only hereditary peer during the last century to have served in the three great Departments of State (Foreign and Home Offices and Treasury) and while in the Treasury was also Paymaster General. He was created a Privy Councillor to Her Majesty The Queen in 1990.
Since 1994 Malcolm has been doing consultancy work for various companies and jointly founded Victoria Soames Ltd., and more recently Rickett-Tinne, a flourishing London Real Estate Agency. As one of the 92 remaining hereditary peers he also still takes an active part in politics from the backbenches in Parliament in legislation and debates as well as serving on committees.
The title of The Earl of Caithness was granted in 1455 to the Sinclair family under Scottish Law and Malcolm is the 20th person to hold the title. He is also hereditary clan chief of the Sinclairs – a position he has held for over fifty years since his father’s death. He has taken an active and prominent role in the clan for the last twenty years. He helped found and is chief executive of the Clan Sinclair Trust, a heritage charity, and was a Trustee of the Queen Elizabeth Castle of Mey Trust for twenty years.
He now lives in London and is married to Penny. He has two children from a previous marriage.