I've seen a number of threads that deal with the postwar political realignment of British politics, where the Liberal Party declines from their once prominent position to be replaced by Labour, with their votes (and more than a few MPs) getting divided between Labour and the Tories. Some of these threads explore the Liberals holding out, or Labour failing to rise, or one party coming to dominate entirely. Your challenge is to find a way for British politics to be dominated by a Liberal/Labour duopoly, with the Conservatives dwindling into the wilderness. Understandably this is no small task, so feel free to use any time after 1900 for PoDs.
hmm well. Lets see.
Scenario one. There is no great war. The Liberals are in Government and bring forward the Government of Ireland Act. The Conservatives are pushed into supporting a General mutiny of Ulster Unionist inclined military units in Ireland.
The Ulster Unionists forces over react to protests and massacre a large number of Nationalists/Catholics, including women and children.
This is heavily covered by British and international Media the public reaction is largely hostile and is supportive of a Government hard line.
There is a long sustained confrontation at the end of which the word Tory is seen as another word for murderer and traitor by the majority of the British and Irish public.
Scenario two. The Liberal Party is helped by an earlier extension of mass ownership of radios to perform significantly better in the 1929 General election, in which they did poll 8 Million votes OTL. The famous yellow book based manifesto "We can conquer unemployment" is successfully delivered Labour is converted as a result to Keynesianism.
The Conservative response is split between moderates ie Chamberlin and ultra traditionalist opponents. A coherent response becomes difficult and the Conservatives split, with the majority taking a hard line. This proves suicidal.
Scenario Three is 2 possible versions of a similar departure. Firstly Lloyd George has a more united party due to Asquith having a fatal accident. He feels stronger as a result and does not need the coupon. The liberal party fights and very narrowly wins the 1918 election.
He realises the need to win the peace and pushes forward with "Homes fit for Heroes" after WW1 as a priority, instead of getting involved in foreign adventures. The Conservative response is mixed and divided, but finally bitterly hostile.
This proves a mistake as the Liberal governments programme proves moderately successful economically and further limited welfare reforms are enacted. The Tories fail to adapt and by the 1920's recession have adopted ultra laissez faire policies allied with high tariffs as a policy.
The conservatives almost win several times in the 20's and early 30's on this platform as the Liberal Party has to seek Labour support to stay in office, but by the early 30's the liberal-Labour response is seen to be working much better than the Tory alternatives as the US and Europe test traditional economics to the breaking point. The Tories plummet and never recover.
Some what on the same lines, but less plausibly, the conservatives do not learn the lessons of real politic, helped by Churchill being stubborn and less influence for certain moderate conservatives. They oppose the Labour reforms of 1945 far longer than they should. Labour and Liberals both benefit from Conservative determination to reverse them and in particular abolish the NHS.
Finally Eden refuses to withdraw from Suez after US Economic pressure. US and British relations completely break down and the US actually takes sanctions. There is economic mayhem in Britain and France. The conservative party falls apart under the pressure and forces Eden out, but struggles to find a stable leadership.
The party is humiliated and divided and eventually dwindles into impotent factions.