Members of parliament often impose limits on debate time or content. This gap raises an important puzzle.

British political development has gained more academic interest recently, especially regarding institutional reforms during the nineteenth century. However, a significant topic remains largely unexplored: why MPs regulate their own floor time?

This paper offers a new explanation. It argues that MPs are quicker to agree on restrictive debate rules when facing opposition from both sides (both government and opposition forces) if they share similar policy preferences.

Low polarization between parties seems key here too.

Using newly digitized records, we show this historical pattern across 205 years of UK House debates. Our analysis includes speeches data covering over six million utterances.

This work provides the first systematic test of these ideas for UK parliamentary reforms. It illuminates a long period in Commons history and introduces new ways to measure party polarization.