As a general rule people who are incarcerated in a jail can continue to claim Child Benefits while they are in prison or on remand.
Child Benefit and Prison: This is especially true if your child is with you in prison or if the child you are claiming for is living with someone else and you pay an equivalent sum to them.
Certain situations allow you to transfer the Child Benefit payment to someone else but your Child Benefit payments will stop after eight weeks if your child is being cared for by the local council.
If your child is sentenced to prison or is on remand your Child Benefit payments will stop after eight weeks.
However, you will receive the arrears if they are cleared of the offence.
If you look after your partner’s child or someone else’s child while they are in prison you may be able to claim Child Benefit and Guardian’s Allowance.
For some situations you may also be able to claim Child Tax Credit.
Benefit for Children of Prisoners; UK Rules Updated 2017