The Big Lottery Fund and Comic Relief provided four-year funding of £16m and £4.5m respectively when it started in 2007. Last year, the Department of Health and Comic Relief granted it £16m and £4m respectively for a second phase until 2015.
The campaign, which is modelled on an initiative called Like Minds, Like Mine in New Zealand, aims to change attitudes and behaviour and puts emphasis on measuring impact.
Sue Baker, campaign director, had worked on the New Zealand initiative before returning to England to lead this programme.
Baker, who has experienced severe depression, says mental health charities have collaborated increasingly over the past 10 years, but this takes things to a new level.
"Both charities focus on this issue in their corporate strategies, so it does not represent a departure from what either does," she says. "It's just that the scale of the work is something neither had done before."
The campaign has a clear name and message. Its working title was Moving People, but this changed after a consultation involving 4,000 people with mental health problems.
Those consulted, says Baker, "wanted us to work in an inclusive way with the general public" rather than point fingers.
The creative agency Forster designed the campaign logo and branding. The first phase focused on tackling myths and getting people to recognise mental health issues; the current phase gets people to talk more and focuses on young people.
The campaign currently consists of 35 projects, which involve a range of partners, from the Football Association to energy suppliers.
In 2010, the Institute of Psychiatry surveyed 1,000 people with mental health problems and found that the level of discrimination reported had fallen by 4 per cent in the previous 12 months.
The evaluation cost £2m but Baker says having detailed evidence of success from a trusted organisation was vital in securing new funding.
Bob Nash, Creative director, Watson Phillips Norman
The authors of the Time to Change campaign have faced a truly fascinating challenge: creating mass behaviour change against one of our deepest-seated prejudices - mental health.
It's a subject laden with baggage: fear, derision, even humour. So the campaign needs to tread a delicate path. And I think it absolutely achieves this.
Rooted in a real truth about our uncertainty of how to respond to someone suffering from mental health issues, the message is simple, honest and well cast.
It helps us laugh at ourselves while making a clear point. Where the campaign really scores is in the way it has harnessed national and local campaigns together to achieve remarkable results: a 4 per cent reduction in discrimination is something to be admired.
Total: 9 out of 10