The nightmare of counting MPs before big votes in the Commons

I understand people who find it frustrating that journalists can seem obsessed with numbers rather than substance – but winning votes is the bottom line of politics

A decision to postpone the Brexit deal ballot will mean some recalculating (PRU/AFP/Getty)

“Keep doing the numbers; they’re very useful,” a Labour MP said to me as we passed in the gothic cloister off New Palace Yard. I was torn between pride and alarm – alarm because it seemed MPs might now be using my Twitter account as a reliable source of information about how their fellow members are intending to vote.

Predicting close votes in the House of Commons is a nightmare. I understand people who find it frustrating that journalists are obsessed with who will win, rather than with the substance of who ought to win and why. But winning votes is the bottom line of politics. You can be as right as you like, but unless you win the votes, it doesn’t matter.

So that is why I post updates on Twitter trying to add up the numbers before big votes. But the scope for getting things wrong is great, because any vote in the Commons is complicated, with 650 movable parts.