Roberts was born in Chedgrave on 27 July 1868: his parents, George Henry Roberts, butcher and shoemaker, and Ann (nee Larkman) had married in Chedgrave church on Christmas Day in 1867. The family moved to Norwich when Roberts was still a child: he did well at school, becoming a monitor at the age of eleven and thus earning a few pence a week. As was normal at that time, he left school at thirteen, becoming an apprentice to a printing firm.
Roberts soon became a leading trade union man in the city. He was a member of the printers' union, the Typographical Association, and rapidly became president and secretary of the local branch. In 1898 he was elected president of the Norwich Trades Council.
In 1899, Roberts stood for the School Board for the Independent Labour Party. He campaigned for the raising of the school leaving age to sixteen, free maintenance for all school children, and for class sizes to be restricted to a maximum of 30 - and also for a purely secular education. There were nineteen candidates for the fifteen seats: Roberts came sixth with 11,387 votes. This was the first victory for Labour in Norwich at any level
Norwich was a two member constituency: voters could choose two members. It was one of several seats where Labour and the Liberals worked together. There was a false start in a Parliamentary by-election in Norwich in 1904, Roberts stood for Labour but came third behind the Liberals and Conservative candidates. However, in 1906, he stood in tandem with a Liberal, Louis Tillett, and the two men were elected.
Roberts was one of 29 Labour Representation Committee members in Parliament, almost all elected because the Liberal Party had not put up candidates to oppose them. Their first acts after the election were to change their name to the Labour Party and to elect Keir Hardie as their leader. He appointed Roberts as his parliamentary secretary, and in the following year he chose him as whip of the Labour MPs in Parliament. In 1912 he became Chief Whip, a position which was his stepping stone to high office. Despite his role as a whip he frequently asserted his independence of mind, voting against the Labour official line on several issues, voting for an increase in the number of battleships, for example, and voting for the Cat and Mouse Act, an act directed against suffragettes to which the Party was strongly opposed.
The outbreak of war in August 1914 split the Labour Party. Roberts was in the 'pro-war' camp: he supported a Government request for a war credit of £100 million, and was happy to help in the recruiting campaign. By the spring of 1915, people were becoming dissatisfied with the conduct of the war, and Asquith was forced to bring the other parties into a coalition. Arthur Henderson, the leader of the Labour Party, came into the Cabinet and other Labour MPs received lesser positions, including Roberts who became a Junior Lord of the Treasury. In December 1916 there was a plot to replace Asquith with Lloyd George, who was seen as a much more charismatic leader. Roberts became Parliamentary Secretary to the Board of Trade in Lloyd George's government.
In August 1917, Roberts became Minister of Labour. This was to be the pinnacle of Roberts' career: the son of a village shoemaker had achieved the rank of a minister in His Majesty's Government.
In the summer of 1918 the Labour Party decided to withdraw its support for Lloyd George's coalition. Labour ministers in the Government had a straightforward choice: stay in government and leave the Labour party, or leave the government and stay in the party. Four ministers, including Roberts decided to break with the Labour Party and stay in the Government.
Lloyd George wanted to continue in power at the head of the coalition that had supported him during the war. He gave each supporter of his coalition a letter, known as the coupon. Roberts received the coupon and was re-elected under the title 'Coalition Labour'. He was appointed Minister of Food, or Food Controller as he was commonly called, in January 1919. At first he declined Lloyd George's offer of this post, but the Prime Minister persuaded Roberts to take the job: however, he resigned the office after thirteen months. He stood for Norwich in the 1922 general election as an Independent - and won. This result was a great personal triumph for Roberts who received his highest vote ever: standing without the support of any party, it was a tribute to his personality, and to his achievements as an MP over the previous sixteen years:
He sat in Parliament as an Independent for ten months, and then completed his political journey to the right: in October 1923 he joined the Conservative Party! Norwich Conservatives immediately adopted him as one of their candidates for the next election, which was held in December 1923. This time, Roberts could not carry the people of Norwich with him: he was defeated by the two Labour Party candidates.
Like many ex-ministers, he then took up business interests, including the promotion of Norwich-made Wincarnis. An inveterate smoker he had health problems and died on 25 April 1928 at Edenhurst, Sevenoaks, a hotel where he had been staying on his doctor's advice: he was 59 years old. He is buried in Earlham cemetery.