Around the time of Charles Kennedy’s death I spent a lot of time talking to his Lib Dem colleague, Norman Lamb. I didn’t know him very well but had always felt, when he was a health minister, that he and Nick Clegg got mental health on the coalition agenda in a way that would not have happened had the Tories been left to their own devices.

So once his unsuccessful leadership campaign was out of the way, we started a discussion which led, a few weeks ago, to the idea of a cross-party, cross-society campaign aimed at persuading the government to do more for mental health in the upcoming spending review. To make sure this was not easily dismissed as just another Lib-Lab call for more spending, we felt it important to have a Tory politician on board from the off. I had been aware that Andrew Mitchell has his own interest in and understanding of mental health, having at one point being treated for depression, and he agreed immediately to join us.

And that has been the story concerning pretty much everyone the three of us have since approached for support. In a matter of a few weeks we have gathered a pretty impressive collection of names lending their support to the call. Politicians of all parties, religious leaders including the Archbishop of Canterbury, senior military figures, leaders in sport, business, arts and culture – the depth and breadth of the support has been remarkable.

I hope and believe it means that we are reaching a tipping point in terms of people’s interest in, awareness of, and desire to end the injustice of inferior treatment for mental illness. If we had been doing this campaign even a few years ago, I think we would have struggled to get the kind of names you can see below.

My worry is that though understanding and awareness are improving, services are not. There is a real danger that the Tories are allowing mental health to slip down the agenda and cuts are happening piecemeal all over the country. They talk the talk – David Cameron did so again at his party conference, and has also welcomed our campaign today  – but if they are serious there has to be more investment in mental health services. I think the reason so many business people and a clutch of former Tory health secretaries signed up so readily is because they realise that investment now can lead to improvements for NHS budgets and the economy down the track.

Five pleas if I may. Log on to Read the statement setting out the argument we are making and the ten areas of concern. Study the names who are supporting our call for more investment. Then  add your own. And spread the word, using the hashtag #Equality4MentalHealth where appropriate.

Mental health is an issue whose time has come. The public are ahead of most of the politicians on this. But the pressure has to be maintained.