If you want to vote in the General Election as an ex-pat today is the last day to register as a voter (applicable to anyone who has left the U.K. within the past 15 years).
Due to postal delays the Electoral Registration Officers are allowing registration by fax and then, again because of the postal delays) a vote using a proxy.
The registration form can be downloaded and the phone/fax number is shown when you enter your last U.K. post code.