More than two million public sector workers are set to receive support to better understand their own and others' mental wellbeing.

It follows revelations in a government-backed report that 300,000 workers leave or lose their jobs each year due to mental health problems– costing employers up to £43bn annually.

The Thriving at work review by mental health campaigner Lord Dennis Stevenson and Paul Farmer, chief executive of charity Mind and chairman of the NHS mental health taskforce, includes 40 recommendations for the public and private sector.

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Prime minister Theresa May, who commissioned the review, announced on Thursday that NHS England and the Civil Service – two of the country's largest employers – will abide by its recommendations. These include:

– Introducing core standards to ensure employees have the knowledge, tools and confidence to understand and look after their own mental health, and that of their colleagues

– Putting support in place to help prevent mental illness being caused or worsened by work, and equipping those who have a mental illness to thrive

– Being held to account for delivering these standards by their relevant regulators.

Mrs May said there was a need to 'take action'.

'I have made it a priority of this government to tackle the injustice of mental illness. Vital to this is the need to have a comprehensive cross-government plan which transforms how we deal with mental illness not only in our hospitals or crisis centres but in our classrooms, shop floors and communities,' she said.

'So we need to take action. That's why I am immediately asking NHS England and the Civil Service – which together employ more than two million people – to accept the recommendations that apply to them.

'With so many of our leading businesses leading the way in this area – and reaping the rewards as a result – I am sure that the private sector will follow suit.

'It is only by making this an everyday concern for everyone that we change the way we see mental illness so that striving to improve your mental health – whether at work or at home – is seen as just as positive as improving our physical wellbeing.'