Childline is holding one counselling session on average every five minutes for young people worried about their mental health and wellbeing during the coronavirus lockdown.
Some 16,644 counselling sessions were given to children with mental health concerns between March 23, the start of lockdown, and May 10.
The NSPCC, which runs the support line, said this was more than half of the total 30,868 sessions delivered during the seven-week period.
This equates to around 339 sessions a day, or roughly one every five minutes.
In comparison, over the 2018-19 financial year, a total of 71,283 counselling sessions were held for children with mental health concerns in the UK.
This means the service has delivered almost a quarter (23%) of last year’s total mental health counselling sessions within seven weeks, when looking at the total sessions over lockdown.
Some 36% of sessions during the lockdown mentioned concerns about mental or emotional health, 13% touched on suicidal thoughts and feelings, 12% on family relationships, 6% on self-harm, and 4% on sex, relationships and puberty.
And around 120 sessions mentioned coronavirus on average each day, with 5,880 sessions – around a fifth of the total – taking place during lockdown.
Between January 10, the first time a child mentioned coronavirus when contacting Childline, and May 10, there were 6,938 sessions delivered which mentioned coronavirus.
The NSPCC also said use of Childline’s Calm Zone, an online tool to help young people manage their feelings, had increased four fold during lockdown.
In early March, it was being accessed around 2,400 times a week, rising to 10,000 weekly page views in April.
It is urging the public to donate to its urgent appeal, Still Here for Children, launched in April.
Dame Esther Rantzen, who founded Childline, said: “Children and families have faced extraordinary challenges because of the coronavirus pandemic, and the next few months will be no different.
“Childline provides a vital lifeline to young people who are trying to cope with the fear, anxiety and distress caused by the pandemic.
“We know from the counselling sessions we have delivered that children’s mental health has been directly impacted and those children who are living in homes which are not safe – where there is violence, addiction or abuse – are finding it especially difficult during lockdown.
“Young people in times of stress often find that their friends and the security of school are crucial to their mental wellbeing, but now they are without them, and are isolated and alone.
“It is imperative that we are there, particularly for those whose usual support networks are not in place and have nowhere else to turn.
“We are urging the public to support our Still Here for Children appeal so we can continue to support our young people whose lives have changed overnight.”
Childline said there has been little change in concerns pre and post-lockdown, but that the crisis has exacerbated young people’s worries and circumstances.
These include can include abuse, domestic violence and difficult family relationships.
An 18-year-old girl told Childline: “I am scared about the Coronavirus. I’m finding it hard to cope at the moment and it feels like it’s the end of the world.
“When I was little I developed OCD and had been to therapy which has helped me to deal with the stress better.
“However, the Coronavirus has triggered it again and I’m really struggling, I don’t know what to do. Please help.”