My understanding on this matter is that prisoners will be able to vote either by proxy or by post. Where they do not have permanent home addresses, and many will not, they can use the address of the prison.
Parliamentary Voting System and Constituencies Bill
Proceeding contribution from
Lord Corbett of Castle Vale
(Labour)
in the House of Lords on Wednesday, 19 January 2011.
It occurred during Committee of the Whole House (HL)
and
Debate on bills on Parliamentary Voting System and Constituencies Bill.
Type
Proceeding contribution
Reference
724 c467 
Session
2010-12
Chamber / Committee
House of Lords chamber
Subjects
Librarians' tools
Timestamp
2023-12-15 14:18:14 +0000
URI
http://data.parliament.uk/pimsdata/hansard/CONTRIBUTION_703860
In Indexing
http://indexing.parliament.uk/Content/Edit/1?uri=http://data.parliament.uk/pimsdata/hansard/CONTRIBUTION_703860
In Solr
https://search.parliament.uk/claw/solr/?id=http://data.parliament.uk/pimsdata/hansard/CONTRIBUTION_703860