This was the result of the 1923 general election...
NI Nationalists 3
Scottish Prohibition 1
OUTCOME : Labour minority government.
If Labour or their sycophantic chums in the press actually believe one word of the lies they've been churning out about so-called "British constitutional rules" over the last 48 hours, they'll have a murderously hard job explaining how the above outcome was even theoretically possible, let alone how it happened so easily in reality. Labour were miles behind the Tories, more so than was even the case in 2010, and yet they were able to form a government without entering into coalition with the Liberals, and without even a formal deal with the Liberals. Why? Because the real constitutional convention is that the monarch must appoint a Prime Minister who commands a majority in the House of Commons. The Liberals held the balance of power, and they were absolutely opposed to the continuation of Tory rule, just as the SNP are now. That made any form of Tory-led government a complete non-starter, irrespective of the fact that the Tories were the largest single party.
Nor, Torcuil Crichton, was it the case that the Tories' status as the incumbent government got them off the hook in 1923. The only special privilege that the incumbent Prime Minister has in the event of a hung parliament is the option to hold on until the reconvening of parliament, and to see if he or she can command a majority in the House on the Queen's Speech (or King's Speech) vote. If that vote is lost, the Leader of the Opposition will immediately be invited to form a government instead.