Unsatisfied with merely winning the election in the UK, Starmer went mad with power, and under his command Labour drove the Tories out of the UK. Terrified former Conservative MPs fled before them, retreating towards Russia, who had always reliably helped them before, but they discovered to their horror that Russia was now backing Reform, and they soon found themselves trapped between two advancing armies.

The Lib Dems were just on holiday in Switzerland, hoping to get some good photos of Ed Davey skiing so that people would notice them. Rumour has it they did notice a couple of Tory MPs running past, but decided not to help, because they weren't falling for that a second time.

The EU said "look, can you guys go and do this somewhere else?"

However, Starmer's bloodlust could not be sated, and the slaughter continued...

WAR WITH SPAIN! WAR WITH SPAIN!

The British government finally heeded the call to stop the dastardly Spaniard once and for all, precipitating a wider conflict which split the continent. Switzerland elected to stay neutral, but to put a 5p charge on plastic bags. The French initially sided with Spain, before the Parisian workers gloriously arose, up with the barricades, down with the government, and sided with their British comrades. The Germans seized the moment to reconstitute the Holy Roman Empire, on the basis that no one was paying attention, but overreached with an attempt to reconquer Poland and the Low Countries, to which the Britannic-French People's Alliance responded with remarkable swiftness, cunningly ignoring Belgium et al and striking directly at the heart of the Hun. The Russians, never ones to let a good opportunity to invade Poland from the East pass by, struck simultaneously, leading to the scenario pictured in the map.

The Tories turned it around and won the 2024 election with "Why only Brexit the UK when we can Brexit all of Europe?"

Jeremy Corbyn enters the War:

Who do you think. You are kidding. Mr. Starmer? If you think we're not running for election. We. Are the Left. Who will stop your little game. We. Are the Left. Who will make you think again. 'Cause who. Do you think. You are kidding Mr. Starmer? If you think old Labour's done?

We never should have stopped at Berlin.

The UK and France finally putting aside their differences to unite under the same red banner of communism and liberating the rest of Europe from capitalism

The HOI4 mod no one asked for

Someone insulted sausage rolls and beans (the breakfast of champions) and it escalated hard. Europe has always been the board on which we like to play out our grievances anyway.

Looks like an open-and-shut case of gunpowder, treason, and plot.