The emotion on display during five hours of heated discussion speaks to the complexity and importance of the bill itself

Who would have guessed? All too often debates in the Commons are partisan affairs, punctuated by jeers and braying. Where reason is superseded by dogma and ill-temper. This was a very different occasion. Parliament on its very best behaviour. Where necessary, people – mostly politely – agreeing to disagree. MPs heard in silence. Some in tears. Even more remarkable was the feeling there was intelligent life on view. The quality of argument was a cut above the average.

There again, this was no ordinary debate. Most Fridays, Westminster is a ghost town with MPs back home minding their constituencies. But this was an exception. The day when a private member’s bill to legalise assisted dying for terminally ill people took its first step to becoming law. When some men and women of faith tried to imagine making laws for those of no faith.

Taking the Lead by John Crace is published by Little, Brown (£18.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.