Jak was born in London’s West End on 11 March 1927, the son of a tailor. He was educated at Clipstone Road School and Lyulph Stanley Central School, and studied at Willesden School of Art. His three years of National Service were mostly spent in the Army Education Corps teaching conscripts to paint, while his first job involved retouching pubic hair on photographs for Health & Efficiency. He went on, in the early fifties, to work with Keymers Advertising Agency, and to make his first contributions to Punch, Lilliput and other publications. In 1952, he joined the Evening Standard, first as an illustrator on the television page and, after thirteen years, as Political Cartoonist (succeeding Vicky).
From 1966, the political cartoons were collected in annuals and, like those of his model Giles, were bought avidly as Christmas presents. However, one of his cartoons ‘Homo-electrical-sapiens Britannicus 1970’, proved highly unpopular with certain sectors of his public, notably union members, and nearly resulted in the Standard’s closure by industrial action. He also drew for the Daily Express, and later the Saturday edition of the Daily Mail and the Mail on Sunday. A founder member of the British Cartoonists’ Association (1965), he was voted Political/Social Cartoonist of the Year by the Cartoonists’ Club of Great Britain (1985). He died on 27 July 1997.