If an MP swaps political party mid-term, a by-election is mandatory in 25 days. — 8 signatures. Status: rejected.
Force an MP who changes political party, (to a different political party), mid-term to resign. Making a by-election in that MP's constituency mandatory.
Democracy and Constituents deserve the right to reaffirm their faith (or otherwise) in their MP, especially after the MP makes such a dramatic change in their personal beliefs.
View this petition on the official UK Parliament website