Good luck. In 2022, there were fewer than 25,000 psychiatric care beds in the UK, for a population of 67 million, or one bed for every 2680 people.
https://www.statista.com/statistics/473278/number-of-psychiatric-care-beds-in-the-united-kingdom-uk/
Just prior to the big "care in the community" push in the early 1980s, there were about 85,000 beds, for a population of 56 million, or one bed for every 659 people.
https://hansard.parliament.uk/Commons/1997-11-27/debates/62d0a01a-2264-482f-a042-1b9f72bdb210/PsychiatricBeds
In other words, we've got a quarter of the psychiatric hospital places, per person, that we had in 1980.
Doctors and other mental health workers want people who are desperately ill to be able to stay in hospital until they're truly well enough to go home, or, say, to be able to have a gradual return with nights at home but keeping their hospital place. But they have to kick desperately unwell people out of hospital because someone even worse off needs their place. And running at less than full capacity is unthinkable, when so many people need a bed but can't get one — even though you need spare spaces for emergency admissions.
When someone is so seriously unwell that they need to be admitted to a psychiatric hospital right now, their doctors and their families would usually like to be able to admit them straight away to the local psychiatric ward. Instead, patients wait, often with only their family to try and keep them safe if they're lucky, while staff call around the country to see if there's a bed anywhere. If they're lucky enough to find one, the patient is locked up potentially hundreds of miles from home — no family support, no visits. If not — well, the person might still be sectioned, but with nowhere to go.
Doctors would like to be able to do planned admissions like they used to, to prevent deterioration or to monitor trying a new medication. No go.
People used to be voluntarily admitted sometimes, and the wards they were admitted to were places with patients with various levels of severity. Now, wards are temporary holding pens crammed full of only the most severely and dangerously unwell people, a place for chemical stabilisation at best, not a place to start getting well.
Psychiatric patients are crying out for more beds, mental health services are crying out for more beds, for people who are so severely, acutely mentally unwell that the average person would be agog that they weren't in hospital weeks ago, long before they reached this point. Just being psychotic or suicidal isn't high enough severity.
Families live on suicide watch, retrieve psychotic family members from abroad, watch loved ones sink into squalor or homelessness or chaos, and none of these things are necessarily severe enough to qualify for one of the very few beds left. Psychiatric patients kill themselves, ones who might've been kept alive and recovered, if inpatient treatment had been available.
None of these things is enough to convince our government to fund adequate inpatient care for mental illness. God only knows how many avoidable deaths and how many ruined lives that adds up to.
I suppose it's entirely possible that our governments will change their minds and decide it is worth spending the money on, when it's the deaths and ruined lives of a tiny number of people who don't have a mental illness, or a mentally ill family member, themselves (rather than the much larger number of deaths and ruined lives they're happy to accept for the mentally ill and their families). But they'll have to find at least four times as many staff, at least four times as many adequate physical facilities, and spending all that money on mentals when there's Hardworking Families out there will be a hard sell.
By the way, how are you intending to distinguish the hundreds of thousands of people with schizophrenia who will never harm anyone in their lives from the ones who are so dangerous they should be secured away from society? I'm sure you're not advocating for life sentences for people who've committed no crime beyond having a mental illness that's beyond their control, who have never harmed anyone and never will?