The Imperial Wireless Chain was a strategic international communications network of powerful long range radiotelegraphy stations, created by the British government to link the countries of the British Empire. The stations exchanged commercial and diplomatic text message traffic transmitted at high speed by Morse code using paper tape machines. Although the idea was conceived prior to World War I, the United Kingdom was the last of the world's great powers to implement an operational system. The first link in the chain, between Leafield in Oxfordshire and Cairo, Egypt, eventually opened on 24 April 1922, with the final link, between Australia and Canada, opening on 16 June 1928.

Guglielmo Marconi developed early practical radio transmitters and receivers, and radio began to be used for practical ship-to-shore communication around 1900. His company, the Marconi Wireless Telegraph Company, dominated early radio. In the period leading up to World War I, long distance radiotelegraphy became a strategic defense technology, as it was realized that a nation without radio could be isolated by an enemy cutting its submarine telegraph cables, as indeed happened during the war. Starting around 1908, industrialized nations built global networks of powerful transoceanic wireless telegraphy stations to exchange Morse code telegram traffic with their overseas colonies.

In 1910 the Colonial Office received a formal proposal from the Marconi Company to construct a series of wireless telegraphy stations to link the British Empire within three years. While not then accepted, the Marconi proposal created serious interest in the concept.

A dilemma faced by Britain throughout the negotiations to establish the chain was that Britain owned the largest network of submarine telegraph cables. The proposed stations would directly compete with cables for a fixed amount of transoceanic telegram traffic, reducing the revenue of the cable companies and possibly bankrupting them.^{[citation needed]}

Parliament ruled out the creation of a private monopoly to provide the service and concluded that no government department was in a position to do so, and the Treasury were reluctant to fund the creation of a new department. Contracting the construction to a commercial "wireless company" was the favoured option, and a contract was signed with Marconi's Wireless Telegraph Company in March 1912. The government then found itself facing severe criticism and appointed a select committee to examine the topic. After hearing evidence from the Admiralty, War Office, India Office, and representatives from South Africa, the committee unanimously concluded that a "chain of Imperial wireless stations" should be established as a matter of urgency. An expert committee also advised that Marconi were the only company with technology that was proven to operate reliably over the distances required (in excess of 2,000 miles (3,200 km)) "if rapid installation and immediate and trustworthy communication be desired".

After further negotiations prompted by Treasury pressure, a modified contract was ratified by Parliament on 8 August 1913, with 221 Members of Parliament voting in favour, 140 against. The course of these events was disrupted somewhat by the Marconi scandal, when it was alleged that highly placed members of the governing Liberal party had used their knowledge of the negotiations to indulge in insider trading in Marconi shares. The outbreak of World War I led to the suspension of the contract by the government. Meanwhile Germany successfully constructed its own wireless chain before the war, at a cost equivalent to two million pounds sterling, and was able to use it to its advantage during the conflict.

With the end of the war and the Dominions continuing to apply pressure on the government to provide an "Imperial wireless system", the House of Commons agreed in 1919 that £170,000 should be spent constructing the first two radio stations in the chain, in Oxfordshire (at Leafield) and Egypt (in Cairo), to be completed in early 1920 – although in the event the link opened on 24 April 1922, two months after the UK declared Egypt independent.

Parliament's decision came shortly after legal action initiated by Marconi in June 1919, claiming £7,182,000 in damages from the British government for breach of their July 1912 contract, and in which they were awarded £590,000 by the court. The government also commissioned the "Imperial Wireless Telegraphy Committee" chaired by Sir Henry Norman (the Norman Committee), which reported in 1920. The Norman Report recommended that transmitters should have a range of 2,000 miles, which required relay stations, and that Britain should be connected to Canada, Australia, South Africa, Egypt, India, East Africa, Singapore, and Hong Kong. However, the report was not acted upon. While British politicians procrastinated, Marconi constructed stations for other nations, linking North and South America, as well as China and Japan, in 1922. In January 1922 the British Chambers of Commerce added their voice to the demands for action, adopting a resolution urging the government to urgently resolve the matter, as did other organisations such as the Empire Press Union, which claimed that the Empire was suffering "incalculable loss" in its absence.