Kelley opposed the Vietnam War. In March 1967 he signed an advertisement in "The Times" calling on the government of the United Kingdom to "dissociate itself explicitly from the bombing of North Vietnam", and in April that year he was one of 59 Labour MPs to vote against the Labour government in a Commons motion on the war. He rebelled against the incomes policy of Harold Wilson's government, voting against the government in a division on the report stage of the Prices and Incomes Bill in June 1968, and voted against the government again in a further motion on Vietnam in December 1969.