15. Pen

PWP held the seat; the winning margin narrowed from 10.3% to 0.8%.

• Won on a lower shareIts own vote share fell 15.6% — it held because the rest of the vote was more divided.
• Vote fragmentedThe top two took only 71.1% between them, down from 92.7% — the field split more ways.

Written from the constituency figures by a fixed set of rules — no language model.