What changed London's mind was the Germans. In November 1882, an article in Allgemeine Zeitung had called for German annexation of New Guinea. When Germany actually did stake a claim in 1884, establishing German New Guinea on the northeast coast, the British could no longer treat the island as someone else's problem. Australian colonies - Queensland loudest, but New South Wales and Victoria too - had been agitating for the British to act. They saw New Guinea as strategically vital and commercially promising. London, which would end up paying for none of the administration, finally moved. In October 1884, Commodore James Erskine of the Australia Station was ordered to Port Moresby to proclaim a British protectorate over the southeastern coast.

Erskine arrived in Port Moresby and found that Hugh Hastings Romilly had already raised the flag on 21 October - having misread a telegram from Lord Derby. A second proclamation and flag-raising was held anyway on 6 November, with Erskine presiding. A "grand assembly" took place aboard HMS Nelson, where British officials hosted local chiefs with speeches, gifts, a feast, and the ceremonial firing of the ship's guns. The chiefs were presented with an English copy of the proclamation. Missionaries attempted to translate its meaning for them. Whether the chiefs understood that the flag-raising signaled the transfer of their land to a foreign empire - or whether the missionaries themselves understood what the chiefs thought they were agreeing to - the written record does not say. Further flag-raising ceremonies continued along the coast for the next month, ending at Teste Island on 26 November. The Papuan chiefs whose lands were now British had not, of course, been consulted about any of this in advance.

British New Guinea had a strange legal position within the empire: it was legally subordinate to Queensland. London would not fund it. The administration was paid for entirely by Queensland, New South Wales, and Victoria, who considered the territory strategically theirs. The administrative structure barely worked. The first special commissioner, Peter Scratchley, did not reach Port Moresby until August 1885 and died of malaria four months later. Former Queensland premier John Douglas took over in 1886, and struggled with what the records describe as a lack of funds, staff, and equipment. British authority over the interior was mostly theoretical - the British minister Evelyn Ashley described the protectorate's extent as stretching "as far as local circumstances may demand," which meant wherever a Royal Navy gunboat could reach. Several punitive expeditions were conducted during the protectorate years by Royal Navy vessels from the Australia Station, against villages that failed to recognize the new order.

On 8 June 1888, letters patent made it official: British New Guinea became a Crown colony of the United Kingdom. William MacGregor, appointed as the first administrator under the British New Guinea (Queensland) Act 1887, proclaimed the colony at Port Moresby on 4 September 1888. MacGregor was the kind of colonial administrator the Victorian empire produced in quantity - a Scottish-born physician, explorer, and magistrate who would serve for a decade in New Guinea and leave a significant mark on its early governance. But he was, still, an administrator of a colony that London barely wanted and Queensland couldn't really afford. When the Australian colonies federated in 1901, the obvious solution was to transfer the whole thing to the new Commonwealth of Australia.

On 18 March 1902, King Edward VII issued letters patent transferring British New Guinea to the authority of the Commonwealth of Australia. The governor-general of Australia replaced the governor of Queensland as the constitutional authority. A new administrative framework - the Territory of Papua - was legislated in the Papua Act 1905, passed on 16 November of that year and taking effect 1 September 1906. British New Guinea, as such, ceased to exist. Its successor, Australian-administered Papua, would govern the same territory until Papua New Guinea's independence in 1975 - 69 years as an Australian territory, 18 as a British one. The colonial arc runs only a single human lifetime, from first flag to final handover. The people who were living there the whole time, of course, measure their presence in something rather longer.