A large amount of MPs from across the political spectrum are opposed to giving prisoners the right to vote in elections.
David Cameron said the idea made him feel sick, while in a non-binding vote in Fenruary, MPs voted overwhelmingly by 234 to 22 to maintain the blanket ban.
In its ruling in 2005, the European Court of Human Rights said denying prisoners the vote was a breach of their human rights.
While individual countries could decide which prisoners were not entitled to vote, it said a blanket ban was illegal.
More top news
Charities warn that sitting down too long can lead to health risks such as type 2 diabetes and cardiovascular disease.
The Labour leader will use a speech to set out the differences between his party and the Conservatives with particular emphasis on the NHS.
Kate will join Prince William on a tour of the Stephen Lawrence Centre before visiting a charity working with disadvantaged young people.