Secret Ballot?

Is it me or has anyone else noticed that ballots at Election are no longer secret ? When did this happen I don't remember any law been passed. Was I asleep that day.
When you go to cast your vote you are crossed off the list and handed a voting slip which is numbered and relates to the name on the list. I tried once to swap with my wife and was told I couldn't .
Anyone know when this started Was it part of Big Brother Blairs' tricks to know what we are all voting for as well what we have for breakfast ! Please let know what you think