On its first night in 1986, more than 50,000 children tried to call Childline. Forty years on, Natalie Dormer tells the story of the helpline that changed everything. In this independent three-part documentary series, Natalie goes inside Childline to meet the Volunteer Counsellors who now answer a child every 45 seconds, the people who built the service against the odds, and the children and young people whose lives it changed. From Dame Esther Rantzen's promise on national television to the challenges children face today, from mental health and abuse to social media and AI, Child on the Line celebrates 40 years of Childline and asks what it will take to protect the next generation. Hosted and Exec Produced by Natalie Dormer. An independent Dog Rose production, supported by the NSPCC.