Almost 200,000 youngsters sought help between April and June, nearly double levels seen before coronavirus.
The Royal College of Psychiatrists said that the figures show that the pandemic is taking its toll on children and young people.
The College analysed NHS Digital data on mental health referrals for children and young people aged 18 and under.
It found that between April and June this year, 190,271 children aged 18 and under were referred to children and young people’s mental health services – almost twice the number referred during the same period in 2019 when 97,342 were referred.
Urgent referrals had also risen steeply.
From April to June in 2019, 5,219 children and young people were referred for urgent support. This rose to 8,552 in 2021, the College said.
At the end of June, a total of 340,694 people were in contact with children and young people’s mental health services – a rise from 225,480 in June 2019.
The Royal College of Psychiatrists said that early help for youngsters is “key to recovery” as it called on newly appointed Education Secretary Nadhim Zahawi to prioritise children and young people’s mental health.
The College said that schools should have plans in place to respond to pupils’ mental health needs.
And there must be an increase in investment in staff training to improve the roll-out of Mental Health Support Teams, it added.
Dr Elaine Lockhart, chair of the child and adolescent faculty at the Royal College of Psychiatrists, said: “These alarming figures reflect what I and many other frontline psychiatrists are seeing in our clinics on a daily basis.
“The pandemic has had a devastating effect on the nation’s mental health, but it’s becoming increasingly clear that children and young people are suffering terribly.
“Children’s mental health services must also be properly funded and properly staffed if we are to treat the ever-growing number needing mental health care. Without investment we run the risk of many more needing crisis help.”
A mother whose teenage daughter relapsed into anorexia during the pandemic, who did not wish to be named, said: “The pandemic has been devastating for my daughter and for our family.
“The disruption to her normal routines and socialising really affected her recovery. She was spending a lot less time doing the things she enjoys and a lot more time alone with her thoughts.
“Unfortunately, she relapsed, becoming so unwell she was admitted to hospital and sectioned. After 72 days in hospital with no specialist eating disorder bed becoming available, we brought her home where I had to tube feed her for 10 weeks.
“My daughter urgently needed specialist help for this life-threatening illness, but services are completely overwhelmed because so many young people need help. It’s a terrifying situation for patients and families to be in.”
Tom Madders, director of campaigns at the charity YoungMinds, said: “It is devastating that so many children and young people are in need of mental health support and that there has been such a rise in those who need crisis care.
“The government must urgently invest in children’s mental health services and properly fund mental health support in schools, but there must also be much better support for young people before they reach crisis.
“That’s why we are calling on them to invest in a network of early support hubs, to ease the pressure on NHS services and ensure young people can get help as soon as they need it.”
A government spokesperson said: “We know the past year has brought additional challenges for many children and young people, which is why we’ve prioritised getting them back into the classroom and made their mental health and wellbeing a central part of our pandemic response.
“We’re investing £79 million to expand children’s mental health services, and through our Long Term Plan an additional 345,000 children will be able to access NHS-funded support by 2024.
“Alongside our ambitious education recovery plans, which can be used to support pupils’ mental health and wellbeing, we are also improving the support currently available in schools, including by offering training for a senior mental health lead in schools and colleges.”