Final answer:
The economic depression after World War I caused many Britons to shift their faith towards socialism due to the widespread poverty and inequality resulting from the harsh economic conditions and policies of the time, most notably the Treaty of Versailles.
Step-by-step explanation:
The shift towards socialism in Britain after World War I can be chiefly attributed to the economic depression of that era. This period of severe economic downturn compelled many to look for alternative political systems that might ameliorate widespread poverty and inequality, and as such, socialism's emphasis on the social ownership of the means of production and greater economic equity gained appeal among the British public. The economic policies and conditions post-World War I, specifically the Treaty of Versailles and the subsequent economic unrest, contributed to the disenchantment with capitalism and subsequent shift towards socialism, as people sought for government intervention that was more deeply invested in the welfare of the common people.