It is currently part of health and safety law to have someone responsible for ensuring the provision of first aid in the workplace. This should be extended to include mental health first aid too, with employers required to have a trained mental health first aider.
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One in four people will experience a problem with their mental health each year (Mind.org.uk) and often it is in the workplace that these issues will come to a head, frequently leading to staff needing to take long term sick leave or resign. Having trained mental health first aiders in places of work will mean people can access emergency support when they need it and be signposted appropriately rather than reaching crisis point. This could provide support where people most need it.