A call from Labour MP Luciana Berger for the prime minister to ring-fence mental health spending has received the backing of 160 parliamentarians.

The Liverpool Wavertree MP, who was appointed Shadow Minister for Mental Health by Jeremy Corbyn before resigning in a failed coup, this week wrote to Theresa May, saying: “Money is not reaching the front-line.”

During last week’s Conservative Party conference, May said mental health had been “dangerously disregarded as a secondary issue to physical health” but Berger said May’s words were at odds with reality, arguing that Clinical Commissioning Groups were having to spend less on mental health this year due to cuts.

Writing on Monday ahead of World Mental Health Day on Tuesday, Berger urged May to “commit your government to ring-fence mental health spending… There is precedent with other areas of NHS funding and this would be a transformative policy that would make a real difference to local services”.

With some areas allocating just six percent of their budget to mental health, Berger’s call drew the support of 160 MPs. Health Secretary Jeremy Hunt promised that an extra £1.3 billion would be invested annually by 2021.