Entitlement: CTC entitlement: Competing claims ("main responsibility")
The Child Tax Credit Regulations 2002, Reg. 3(1), Rule 2.
If two or more people make separate claims (that is, not a single joint claim made by a couple) for CTC in respect of a child or qualifying young person, only one claimant can be treated as responsible for that child or qualifying young person for tax credits purposes.
The child or qualifying young person will be treated as the responsibility of whichever of them has “main responsibility”.
“Main” responsibility is not defined in the regulations therefore the term is given its normal everyday meaning - someone who is normally answerable for, or called to account for, the child or qualifying young person.