The Home Office has been aware of the possibility of postal vote fraud for a year but has been willing to take the risk in order to increase the declining number of people voting in elections.

Five councils were given permission to run experiments with postal voting in last May's local elections. The experiments were considered a success with some areas reporting a doubling of the vote. However, there were dozens of complaints from voters worried about electoral fraud.

Gateshead council said that increased postal voting "created opportunities for systematic abuse".

Yesterday, George Smith, chairman of the Association of Electoral Administrators, told Radio 4's "Today" programme: "We are a little worried. There is a possible risk. We think it's well worth running but it's a thing the Electoral Commission needs to look at after the election."

A BBC journalist managed to obtain seven postal votes for dead voters in Torbay, a seat held by the Liberal Democrats with a a majority of only 12 votes.