Mental health nurses and psychiatrists are to work in 999 call centres and ambulances as demand for crisis care has soared.
The move, which was announced as part of NHS winter plans in October and is now being rolled out, will mean that if someone calls for help in a mental health crisis they will get quicker access to a specialist.
Dozens more mental health professionals will work within ambulance control centres and accompany paramedics on emergency call outs, NHS England said.
Data from trusts already piloting the scheme has shown that the move can reduce the number of mental health crisis patients needing A&E treatment.
It comes as demand for mental health crisis services has doubled since 2017.
And since the start of the pandemic, it has increased by a third.
Some 200,000 people a month call 24/7 crisis lines and there are around 90,000 referrals each month to community crisis services.
National director for mental health at NHS England, Claire Murdoch, said: “Getting support to people suffering a mental health crisis quickly is critical and will be even more important over the coming months when the NHS is facing a perfect storm with winter virus cases rapidly increasing alongside ongoing pressures in emergency care.
“The NHS is helping twice the number of people experiencing a mental health crisis compared to five years ago thanks to the rollout of 24/7 crisis support phone lines meaning tens of thousands are receiving the support they need without having to go to A&E.
“The NHS has been planning more extensively for its most challenging winter yet including having trained mental health professionals answering 999 calls and heading to the scene with paramedics to offer treatment at home.
“If you are struggling with your mental health do seek help from the NHS – you can refer yourself online to our world leading talking therapies service or if you are in a crisis, you can call your local helpline 24/7.”
The NHS is also set to roll out around 100 specialist mental health ambulances across the country over the next three years.
Commenting on the announcement, Sophie Corlett, interim chief executive at the mental health charity Mind, said: “This winter is likely to be incredibly challenging for the mental health of millions of people across the country, so it’s great to see NHS England looking to address the huge pressures A&Es are already under as winter sets in.
“When people are in mental health crisis, they need care and support there and then. Supporting our NHS to reduce those pressures by giving people immediate access to a mental health professional either in person or over the phone will help many people to more quickly access the type of care most appropriate for them.”
Mental health minister Maria Caulfield said: “Crisis services can be vital for so many that are suffering and can make all the difference in ensuring someone is seen and treated as quickly as possible – so it’s great that they will be bolstered by more mental health trained staff over this busy period.”