"Some voters have complained in the past that elections in the UK are not secret because there is a number on the back of the ballot paper and also on the counterfoil of the ballot paper book the ballot paper is taken from. It is claimed that a ballot paper could be matched with the counterfoil, which records the electoral number of the voter. It is true that, in theory, votes could be traced in this way. However, in reality, there are procedures in place to ensure that this does not happen.
All procedures during an election are prescribed in law. At the close of poll, the counterfoils of the used ballot paper books are sealed in packets along with other confidential documents used by the Polling Station staff. This happens before the staff leave the polling premises. These packets may only be opened upon an Order from the High Court or the House of Lords.
At the Count, the marked ballot papers are kept face upwards so that no-one may attempt to see the number on the back of the ballot paper. At the end of the Count, the marked ballot papers are sealed in packets in a similar manner to the unused ones before they left the Polling Stations. This all takes place under the scrutiny of independent agents representing the candidates and by the Returning Officer and his staff so that no fraudulent or dishonest practice may take place.
All the documents, sealed in their separate packets, are kept securely in custody by the Returning Officer (or by the Clerk of the Crown for Parlaimentary elections) and are kept for 12 months. This is to allow time for any Court Order to be made if the conduct of the election were to be called into question. Even then, it would not necessarily mean that all packets would be opened and scrutinised. At the end of the 12 month period all the packets are destroyed.
Honest voters have nothing to fear and the ballot is secret."