Your entitlement to most benefits stops while serving a custodial sentence in prison as a result of a criminal conviction.
If you are claiming benefits and about to go into prison or you are on remand, you should contact the office that pays your benefit as soon as possible. The address and telephone details will be on any letters you have received from them. If you can, tell them the date of your likely imprisonment and the length of the sentence. This is to make sure that you are not overpaid any benefits that you are not entitled to while you are in prison.
Most benefits are paid in arrears, so when you enter prison you may be owed some benefits payments. You should inform the office that pays your benefit of your change of circumstances and request the arrears be paid to you in prison or sent to someone who is not in prison who is managing your money.