How can these Smaller Parties be Important in the UK Political System? (EX)

-Can Divert Votes away from the Main Parties [SNP has Kicked Labour out, and UKIP took Votes from Labor and Conservative in 2015] -If a Marginal Constituency appears with the Major Parties, then the Smaller Parties May Split the Vote [Brexit Party didn’t Campaign in Conservative Held, or Marginal Seats, to ensure Labour didn’t have a Chance -Small Parties can affect the Large Parties Policies if they are a Threat [UKIP’s Success at 2014 EU Elections made Conservative promise a Referendum. 2019 EU Elections from Brexit made Conservatives go Harder]