When you roll up to your local polling station on an election day, to do your civic duty and put a cross against your favourite candidate, you’re more than likely to be accosted on the way in by busy people armed with clipboards asking for your voter number.

They’re called tellers – but who are they? Why are they doing this? Should you tell them?
The answer to the third question is: yes, you should. To see why, we have to look at the first two.
The various rival political parties will have been canvassing for the past few weeks, knocking on doors and making phone calls. The purpose of this canvassing, in the run up just before the poll, is not so much to win people over (that’s a slow process) but to identify who might be going to vote for them on the day. With today’s low turnouts – below 50% for many elections – the seat goes to the party that can get its supporters out of their comfortably warm houses to make the trip to the polling station. So each contesting party has its list of the voters they think they can count on, and these lists, although incomplete and of varying accuracy, are vitally useful information for them. And your name is probably on one of them.
So come mid afternoon, in rival committee rooms across the ward or constituency, party volunteers will be setting off to call on their identified supporters to remind them that this is the day, and encourage them to make the trip.
But there’s no point calling on someone if they’ve already been to vote. And that’s where this collection of numbers comes in. When you give your number to a teller, it goes into their system and if your name is on their list of people to call on, it gets crossed off. By giving your number you avoid the hassle of a knock on the door. (Or several knocks on the door, in some cases.) Even if your instinctive response to a request for personal information is to tell the requestor to get knotted, its worth your while to conform this time.
Reading this you may be worried that your personal information is being kept, on computers and hardcopy, by political organisations. It is covered by the GDPR. You can ask what information a local party has about you and demand changes if it’s inaccurate, though I’ve never known of a case. Party volunteers are allowed to use it for political purposes but not for idle curiosity, though that’s unenforceable. You probably should be worried: if a tired canvasser mistakenly puts you down as a red-hot socialist and the information leaks, you are not going to start receiving Facebook posts for Jeremy Cornyn memorabilia, but it could scupper your application to join the golf club.
It’s normally very civilised. Tellers are allowed to ask for numbers, but cannot insist. They can wear rosettes in their party colours, which helps make clear they have no official status, and they absolutely mustn’t try to influence your vote. Tellers from different parties will call out numbers to each other and fraternise like WWI troops during a ceasefire, having shared the same experiences from different sides. When the poll closes the normal hostilities will resume, but for today we’re united against the common enemy of voter apathy.

