CCM6906 - Particular Aspects: Income - Prisoners
From 6 April 2007, a prisoner serving a custodial sentence or on remand awaiting trial or sentence who is working (whether inside or outside the prison) while serving the sentence or remanded in custody, is not engaged in qualifying remunerative work.
However if that prisoner is paid for their work their income should be included as employment income in a joint claim.
This prevents a prisoner from claiming WTC in their own right, but ensures that their income is included as part of the household income in any claim their partner might make for WTC and/or CTC.