Charlotte Caldwell said that Michael McBride was no help to her son Billy

The new head of a panel advising ministers on the medicinal use of marijuana is facing calls to resign after being accused of blocking the treatment of a epileptic boy whose care forced the government to reconsider its position.

The Home Office appointed Michael McBride, the chief medical officer of Northern Ireland, to lead the body. Within 24 hours, however, the mother of Billy Caldwell said that she had “no confidence” in his leadership.

Charlotte Caldwell, 50, told The Times that Dr McBride had been involved in her son’s care for a decade but “never to his benefit”.

“I have no confidence whatsoever in the panel with Dr McBride chairing it,” she said. “I am calling for him to remove himself in view of