I have been involved in elections since I was 6, as my Mum and Dad were both local councillors, so I know what I'm talking about. As Hymie says, they are seeing if you are one of their voters by taking your number (or name/address), but this is useless to them unless you have been previously canvassed to say who you are voting for. Secondly, what they are doing is ILLEGAL. They cannot, by law, ask you anything until you have voted as they may be deemed to be influencing your vote. Legally, they are not even allowed on the premises of the Polling Station, though they can ask the permission of that stations officer, though I have know stations where permission has been refused. In this case they have to wait 'outside the gate' or whatever. I love going to my local polling station and telling the 'number collectors' all this...they seem quite taken aback!