The Cabinet Office has given a £500,000 grant to the BeatBullying Group to expand an online mental health service for children and young people.
The service, called MindFull, is designed to give vulnerable young people access to counselling whenever they need it.
It was launched three months ago to support young people aged between 11 and 17.
The government funding will enable the service to be expanded to cover those aged between 18 and 25 and train more volunteers that can provide advice through it.
BeatBullying was invited to apply for the funding by the Cabinet Office.
The charity received £1.3m last year from the Office for Civil Society’s £20m Social Action Fund to set up We’re Altogether Better, an umbrella group that included BeatBullying and the charity’s existing schemes such as the employment project FutureYou and the CyberMentors peer advice service.
Emma-Jane Cross, chief executive of BeatBullying, said: "This critical funding will make an enormous difference and will allow us to reach even more of the 850,000 young people in the UK who are struggling with diagnosable mental health conditions."
Nick Hurd, the Minister for Civil Society, said: "BeatBullying has a remarkable record in training and mobilising volunteers around a cause.
"By creating such a comprehensive service online, where young people spend so much time and feel comfortable communicating, I’m sure BeatBullying will be able to reach even more of those in need of support.
"That is why we are so pleased to help extend this service to 18 to 25-year-olds and help those during such a crucial transition to adulthood."