The Daily Mirror is a British newspaper, launched on 2 November 1903 by Alfred Harmsworth (later Lord Northcliffe) as a newspaper for women, run by women. In 1904 changed it to a pictorial as unsuccessful and called The Daily Illustrated Mirror. This name ran from 26 January to 27 April 1904. Originally aimed at a middle class readership, in 1934 a decision was taken to increase sales by appealing to working class readers. Based in London, in 1955 the paper also began to produce a Northern edition from Manchester. By 1960 The Daily Mirror was Britain's best-selling tabloid newspaper. It was overtaken by The Sun in 1978. The Daily Mirror was sold to Robert Maxwell in 1984, and produced its first colour edition in 1988. The 1990s were a difficult decade for the paper, which underwent large-scale restructuring. In 1999 The Daily Mirror merged with regional newspaper group Trinity to become Trinity Mirror. Printing was moved to facilities in Oldham and Watford. In common with other tabloid papers, The Daily Mirror saw sales fall in the early 2000s. In 2012 the paper merged with its sister title, The Sunday Mirror.

Allied Newspapers Ltd was a newspaper publishing consortium formed in 1924 following the amalgamation of various newspaper titles, including those of Edward Hulton. The company was renamed Kemsley Newspapers in 1943 and was subsequently bought by Roy Thomson, Lord Thomson of Fleet, in 1959.

The Daily Herald was launched in January 1911 as a strike sheet for the London printing unions, then involved in an industrial dispute, to support their pleas for improved pay and conditions. So successful was the sheet in helping the unions win their argument, that a movement began for the Herald to be adopted as the daily newspaper in support of the socialist cause. In April 1912, this mobilisation of effort resulted in the paper being relaunched as a daily dealing with issues directly relevant to the working man and woman. The early days of the paper were, however, beset by lack of money, even though the Trades Union Congress (TUC) took the paper over in 1922. The paper reeled from one financial crisis to another until, in 1929, Odhams Press stepped in to save it. The financial injection meant that the paper's immediate future was secured and in March 1930 the new Daily Herald was launched. Odhams Press held 51% of the shares, with the remainder owned by the TUC. The immediate priorities of the new owners were to increase the circulation, broaden the socialist profile of the paper and ensure its financial viability. Late 1929 saw a massive drive to achieve these aims. The size of the paper was doubled from ten to twenty pages; rallies and events promoting the new Herald were held across the country; members of the Labour Party were recruited to promote the paper and a prize incentive scheme was implemented where premium cameras and free gifts were given away on purchase of the paper. These initiatives resulted in a steep increase in the Herald's circulation from 250,000 to a million. This trend continued until, in 1933, the Herald became the world's top selling popular daily newspaper, with certified net sales of 2 million. The sharp increase in circulation spurred the Herald's rivals into action; they envisaged the erosion of their financial and political powerbase. Soon newspapers from the more conservative Beaverbrook stable (e.g. the Daily Express) began to solicit support for their publications. The ensuing circulation war took both an immediate and long-term toll on the Herald. The paper's circulation declined. Throughout this period, and for many years afterwards, the Herald continued to espouse official Labour policies, defined by the Labour Party and at TUC conferences. However, whilst its appeal had broadened, Odhams Press felt that the political ties were hampering its growth. Nevertheless, the increasingly uneasy TUC - Odhams relationship managed to last for about thirty years until finally, in 1960, faced with downwardly spiraling sales and the loss of advertising revenue, Odhams persuaded the TUC to relinquish their shares. The slide had, however, become irreversible and, in March 1961, Mirror Group Newspapers (MGN\IPC) assumed ownership of the paper on taking over the Odhams empire. The company began a massive drive to revive the ailing Herald. After an initial period of assessment, MGN\IPC decided to enliven the image of the paper in order to broaden its appeal. In September 1964 the paper was relaunched as The Sun with the slogan 'A Paper Born of the Age We Live In'. Despite this change of image, the paper’s format remained stale and uninspiring. After an initial upsurge in circulation, sales again declined. MGN\IPC decided to cut their losses and in 1969 sold the Sun to Rupert Murdoch's News International, whereupon its content and message completely altered.