Should there be a general election if the Prime Minister resigns?

The UK operates under an uncodified constitution where the Prime Minister leads the government with the confidence of the House of Commons. When a Prime Minister resigns, the monarch invites the leader of the party with a Commons majority or coalition support to form a government, without requiring a general election. Recent speculation surrounds Prime Minister Keir Starmer facing pressure from over 50 Labour MPs to resign amid party crises, prompting public calls for an election to grant a new leader democratic legitimacy.