After his loss, Dallas was appointed to several Government committees set to investigate agricultural and water problems. In 1935, he visited European centres where international gatherings of Labour representatives have taken place to discuss the Italo-Abyssinian dispute. Dallas stood in Wellingborough again at the 1935 general election, cutting the Conservative majority to 372 votes. However, he resigned his candidacy a few months later, partly due to illness. He continued his activities for the Labour Party, and was elected chairman of the National Executive Committee in 1937. He died in Bishop's Stortford, Hertfordshire aged 82.