Last week Chris Grayling announced that, in one of the great scientific breakthroughs of modern times, he had discovered the answer to the West Lothian Question. On Tuesday the Commons seemed a lot less sure that he had got it right.
Some gathered to remember the family members they had lost. Hundreds more came to remember what they had seen and heard, and how they had responded. And as the names of 52 victims echoed under the dome of St Pauls Cathedral, a nation paused to remember an attack on a city that refused to be terrorised.