A serving UK prisoner has mounted a legal challenge to the government's right to deny him the vote. Should he win his case, it would have a profound effect across Europe.
So how does the British government's attitude compare with its counterparts across the world?
The UK, it seems, has plenty of company in denying prisoners the vote. A total of eight European states - mainly from the former Eastern Bloc - have a similar blanket ban, according to the Prison Reform Trust.
In addition, five more countries have no provisions to allow prisoners to vote.
PRISONER VOTING BANNED
Source: Prison Reform Trust
However, these countries are not in the majority. Eighteen states, including the Irish Republic and Spain, put no voting restrictions on prisoners.
But the Irish government admits that, in reality, voting for prisoners in the republic is not so straightforward.
Their website states: "You have a right to be registered in the political constituency where you would normally live if you were not in prison.
"However, you have no right to be given physical access to a ballot box by temporary release, or a postal vote, or any other way."
In other European countries, including France and Germany, courts have the power to impose loss of voting rights as an additional punishment.
The European Court of Human Rights is currently considering the case of UK prisoner John Hirst, who claims his human rights have been abused by denying him the vote.
If he wins, the ruling will force all 46 members of the Council of Europe to give voting rights at least to some serving prisoners.
For the broadest spectrum of approaches to voting rights for convicted criminals, look no further than the United States.
US states differ over voting rights for their prisoners
Overall, 48 states deny the vote to serving prisoners, 33 disqualify parolees from voting, and eight even bar ex-convicts from the ballot box. Only two states - Maine and Vermont - place no restrictions on prisoners.
Conviction rates among ethnic minorities in the US are much higher than rates among white people. As a result, a much higher proportion of black and Hispanic people are excluded from the vote.
This has prompted criticism and even several lawsuits claiming racial discrimination - particularly in Florida, where it is estimated almost one-third of black people are denied the vote.
The state was crucial in deciding the 2000 presidential election in favour of George W Bush and his Republican Party. Many in the defeated Democrat Party blamed the disqualification of ethnic minorities - traditional Democrat voters - for their loss.
REST OF THE WORLD
The European Convention on Human Rights, absorbed into British law in 1998, was not the first piece of legislation to protect the right to vote.
The United Nations enshrined similar rights in its International Covenant on Civil and Political Rights (ICCPR), signed by the UK in 1976.
It states that every citizen should have the right to vote and those deprived of their liberty should be treated "with humanity and with respect for the inherent dignity of the human person".
Inmates often stage protests at Brazilian jails
It adds: "The penitentiary system shall comprise treatment of prisoners the essential aim of which shall be their reformation and social rehabilitation."
South Africa put this into practice in 1999 when all prisoners were given the right to vote.
The South African Constitutional Court declared: "The vote of each and every citizen is a badge of dignity and personhood. Quite literally it says that everybody counts."
Canada is also among the countries to soften its approach recently. In 2002 the supreme court stated that denial of the right to vote "countermands the message that everyone is equally worthy and entitled to respect under the law".
Many other countries give offenders determinate voting bans, depending on the length of their sentences.
The Australian Electoral Commission summarises this approach: "Prisoners serving sentences of less than three years, serving sentences of periodic detention, on early release, or on parole, are entitled to enrol and vote."
But supporters of penal reform say there is still much to be done. China and Brazil, boasting two of the world's largest prison populations, come under frequent criticism for denying prisoners even the most basic human rights.