hmmmm...
In the course of the 1880s and 1890s, the cod stocks off Newfoundland diminish unaccountably. Canadian and British fishing fleets are forced to turn elsewhere for the bulk of their intake. Much of that 'elsewhere' is the Dogger Bank, the waters around Iceland, around Kap Farvel, and the Norwegian coast. Modern British trawlers use high-tech methods to catch large amounts of fish, to the chagrin of the Scandinavian governments. Norwegian and Icelandic fishermen complain that their catches dwindle. Diplomatic notes from Cpopenhagen and Stockholm to Whitehall are ignored - 'It's all in international waters, isn't it?'
In 1898, the navies of Denmark and Sweden (still including Norway) begin patrolling their respective waters. Both governments set up fishing quotas which the British govt refuses to accept. In 1899 and 1900, there are a number of ugly incidents involving British fishing boats boarded and searched, in one cases even detained, by Swedish or Danish warships.
On July 17th, 1901, the Danish patrol sloop 'Hajen' stops the 'Mary Caine' of Hull for alleged violations of the fishing quotas off Godhabt. THe British trawler (guilty) trusts to its modern engine and tries to run. Fearful of a British reaction if they used theirt guns, the Hajen gives pursuit, runs down the trawler and attempts a risky boarding maneuver at speed. It fails, the ships collide and the 'Mary Caine' sinks Three men of the crew die in the icy waters before the Swedish sailors can save them.
In Britain, national indignation boils over. Harshly worded diplomatic notes are drafted and warships make their way to the fishing grounds to protect the lives of British subjects from the savagery of high-handed latter-day Vikings. Beforte the Swedish government can even react to the incident, HMS Lily makes its appearance in Icelandic waters and attempts to interfere with the Swedish gunboat 'Karlskrona' shepherding British trawlers. THe lieut.cmdr. overreacts and fires a warning shot, certain that the barbaric scandinavians are trying to detain the whole fleet ashostages. 'Karlskrona' replies and both vessels suffer heavy damage before 'Lily' is forced to turn back. The gunboat makes it back to Limerick on its last legs. WAr is declared that same night.
The Royal Navy leaves its ports to teach the Swedes a lesson. Swedish Navy patrols are driven off the high seas, Royal Marines land on Iceland and take Rekjavik almost without a fight, and twenty days after the outbreak of hostilities, all Swedish trade is bottled up under blockade. A heroic attemptz at a breakout from Stockholm is beaten back with heavy losees on both sides. NOw comes the clinching point.
a) France (or. less likely, Germany) intervenes on behalf of the Swedes and declares war. WWI follows
b) France, Germany, or Russia intervene diplomatically on behalf of Sweden. A conference is called and the Swedish crown agrees to pay symbolic reparations and open its fishing grounds to British trawlers without limit. The war ends in November 1901 and Iceland's fishing grounds are doomed.
c) The other European powers agree to a hands-off position and Britain attempts an invasion of Sweden that will humiliate and chasten its Army.
I consider b) the most likely, given how busy Britain is at the time and how inconsequential the whole affair after all would seem in retrospect.