Should those who are convicted of crimes so serious that they receive a custodial sentence be able to vote?

Should prisoners have the benefit of influencing the making and reform of laws that they have either admitted to breaking or been shown beyond reasonable doubt to have broken?

According to newspaper reports today, the blanket ban on prisoners being able to vote is at last to be lifted. The spin is that this is because it is too expensive for the government to remain in breach of its obligations under the European Convention on Human Rights (ECHR).