The Children, Schools and Families Select Committee makes the call in a report into the Children and Young Persons Bill, which is currently going through Parliament.

Witnesses giving evidence to the committee as part of a wider inquiry into looked-after children backed the recommendation.

Maxine Wrigley, the chief executive of A National Voice, said the lack of advocacy is the "biggest gap" in the Bill.

"I'm not sure that people have understood the important role that an independent advocate can play," she said. "It is quite distinct from the independent reviewing officer."

The first set of witnesses to appear before the inquiry said they were broadly happy with the latest government proposals to support looked-after children, but outlined some areas of concern.

Pam Hibbert, principal policy officer at Barnardo's said she is disappointed there is not more in the Bill about supporting children in care who go into custody.

Wrigley added: "There are some elements of the Care Matters green paper that have been watered down significantly. One of them is around custody, but the other one is around mental health support."