Britain has become a 'Prozac nation'

In a speech to the Guardian Public Services Summit in St Albans, he will accuse politicians of 'shamefully' ignoring the scale of the country's mental health problems.

The party has obtained figures showing waits of more than two years for some counselling and psychotherapy services. He will commit the Lib Dems to a maximum 13-week wait for treatment for mental illness, with a guarantee that the NHS will pay for patients to go private if it misses the target.