Charities have united in a new campaign from the Money and Mental Health Policy Institute, chaired by MoneySavingExpert.com founder Martin Lewis, to stop NHS doctors charging people with mental health problems up to £150 to fill in a form crucial for them to get debt help.

An investigation by Money and Mental Health revealed one in three who asked their doctor for the 'Debt and Mental Health Evidence Form' were charged for it – some paying as much as £150. This is resulting in people racking up more debt just to pay their GP, or going without the support altogether.

The charge is also hitting the less well-off the hardest, Money and Mental Health's research covering 5,500 people found. A typical GP charge for filling out an evidence form is between £20 and £50, while the vast majority surveyed had incomes of less than £300/week – four in 10 had incomes of less than £200/week.

Money and Mental Health has been backed by a number of other charities in its call for the Government to take action against a charge that can plunge vulnerable people into even more financial hardship.Those who want to support the campaign can sign a joint letter to the UK health secretaries here.

'After the doctor's I didn't have any money left… I couldn't afford fresh food'

One in four people with a mental health problem is also in problem debt. Research by Money and Mental Health has shown that mental health problems can make it harder both to earn and to manage money. For more help, check out our Mental Health and Debt Help free PDF guide.

Many banks recognise this and are willing to offer extra financial support, freezing interest payments or even writing off some debts when people are struggling. But to access this help customers are often asked to provide evidence of their mental health problem, signed by a doctor.

Since 2008, this has usually been done via a single form – the Debt and Mental Health Evidence Form – which is recognised by the credit industry, advice agencies such as Citizens Advice and others.

Ian Hurst, who has depression, says: "I was on really low benefits. Paying £20 for the doctor's note had a big impact; it was a big chunk of the money I had left that week. I didn't expect them to charge me. I was going to go to the shop after my appointment to get food, but after the doctor's I didn't have any money left. Until my benefits came in I couldn't afford fresh food, so had to live on dry pasta and the things in the cupboard."

How come GPs are charging to fill out this form?

While the form is recognised across the credit industry, and used by the likes of Citizens Advice, as it isn't an NHS form the current rules do allow GPs to charge, just as they do for certification that a patient is fit to fly on holiday.

The British Medical Association provides guidelines on how much doctors should be charging their patients to complete certain forms and certificates – for example, for a private sick note required by a patient for presentation to an employer (except for those which the doctor is obliged to provide for statutory sick-pay purposes), GPs can charge between £30 and £63.

However Money and Mental Health is calling on the Government to make the Debt and Mental Health Evidence Form exempt from charges by categorising it as an NHS form, just like the forms that certify a patient has a health condition that makes them eligible for council tax reductions.

'It's time for the Government to act'

The call is backed by Mind, Rethink, StepChange and other mental health and advice charities which together have written to the UK health secretaries to support Money and Mental Health's campaign and to demand change.

Martin Lewis says: "This charge simply isn't acceptable. It's time for the Government to act to stop it. And we have to ask some GPs to change too. Most don't charge, but to those that do, I'd ask 'is it really necessary?'

"We know you're stretched and doing a hard job – but the impact this could have is huge. Mental illness and debt problems can each cause and contribute to the other. To enable people to get help with their debts more easily is likely to have a clinical impact on their mental health issues – for example, research shows that recovery from depression can take longer for those in problem debt."