Deputy Prime Minister Nick Clegg has urged employers to “take a mental health stock check” of their workforce to boost employee wellbeing.

Launching the call to action with Care Services Minister Paul Burstow, Clegg said that 70 million working days are lost to conditions such as depression and anxiety every year.

This costs employers more than £1,000 per employee every year - or almost £30 billion across the economy - through sickness absence or people underperforming, he said.

In the UK, one in six workers currently experience poor mental health, equating to nearly five million British employees. “Business cannot afford not to take mental seriously,” Clegg said.

He urged employers to “take three simple steps” to address mental health issues. These are: signing up to the existing Time To Change campaign pledge to end discrimination against people with these illnesses; getting specific first aid training for mental health; and using the free Health for Work Advice Line in England for advice and support.

“Today I am calling on every employer, large and small, to do a mental health stock take. Too many people suffer in silence with mental health issues. Employers are well placed to recognise warning signs and signpost their staff to support,” Clegg said.

"These three simple steps give all employers the support to look after their staff’s mental health and keep Britain working."

The Deputy Prime Minister highlighted companies such as BT, E.On, Deloitte and EDF Energy for “already doing fantastic work to support their teams”.

BT said its mental wellbeing strategy had led to a 30 per cent drop in mental health-related sickness absence, and a return to work rate of 75 per cent for people absent for more than six months.

The three-step framework is supported by the NHS Commissioning Board and Public Health England and is part of the government’s plans to ensure that mental ill-health is treated as seriously as physical illness. This principle is covered in the Heath and Social Care Act 2012, the government said.

Sean Duggan, chief executive of Centre for Mental Health, said: “The framework gives organisations across the country a clear message about where to start in making the major changes we need to see to improve the life chances of people facing and living with mental ill health.”