To report politics, you have to know how to count

There was a last-minute scramble on Thursday night to try to find out which cabinet ministers had voted against Theresa May

Lyndon B Johnson never said that the most important thing in politics was to know how to count, but if he had he would have been talking about psychology, not arithmetic. As one of America’s supreme political operators, he knew that every member of congress had a price – often literally – and he was good at persuading people. More importantly, he was good at judging whether they had genuinely been persuaded.

That is one of the hardest parts of reporting parliament. Sometimes – and this week was one of those times – it is hard to predict how MPs will vote, and quite hard to explain what they did after they’ve done it.

On Thursday night, in particular, there were two extraordinary votes. First, Hilary Benn, the Labour chair of the Brexit select committee, lost his amendment by just two votes. That was the narrowest margin I have ever seen. I had to look up when the last tied vote was (it was 1980: a vote on televising the Commons, which as a result didn’t happen until 1989 – there was also one in 1993 on the Maastricht Treaty, but that turned out to be an error; the government had actually won by one vote).