Votes can be traced by matching the numbered ballot paper to its similarly numbered counterfoil; the numbered counterfoil also bears the voter’s registration number from the electoral register which is hand-written by the Polling Clerk when the ballot paper is issued. As all the ballot papers for each candidate – including fringe candidates such as Sinn Fein, communists, fascists, nationalists, etc. – are bundled together, anyone having access to those documents can speedily trace the name and address of every voter for such candidates if they wish.
…claimed that the South African government knew the identity of everyone who voted for the Communist Party of Great Britain – thanks to British intelligence using this simple vote-tracing procedure. In any event, the notion that we have a secret vote is very misleading.
Instead of writing over with pen, they’d just reprint your slip and write in what they like.
You could do it with a home printer.