The number of mental health nurses in England has slumped by more than a tenth over the past decade, new figures, in the Guardian, have revealed. This is despite commitments from both Theresa May and her predecessor, David Cameron, to boost resources for mental health services, which many medical professionals say are now in crisis.

Donna Kinnair, appointed as RCN chief executive and general secretary last month, will use a speech to the group’s annual congress on Monday to call on ministers to address England’s 40,000 nursing vacancies, and point out the new figures on the reduction in specialist mental health nurses.

“Thousands of experienced professionals have been lost in recent years as the investment failed to match the rhetoric,” she will say. “The shortage of beds, too, leaves vulnerable people often sent hundreds of miles from home and their loved ones for the care they need. As a country and a health service, we are letting down people who must be able to rely on us most. We must draw a line under this and allocate serious resources to mental health care, including the right number of staff.”

There have already been warnings of a postcode lottery, with some regions having little more than half the resources of the best-funded. According to research from the charity Mind, the average annual spend on mental health services per head of population is £124.48 in parts of Surrey, compared with £220.63 in South Yorkshire.