The UK and the US are similar.
@Raggamuffin hit the nail on the head. A crisis for a long time. Shortage both in staff and funding.
Obviously, the downstream effects of this can range from prolonged mental pain and behavioral issues, to the economic front (job loss, poverty, etc.), to desperate people doing desperate things (crime, sex work, selling drugs), to more self-destructive behaviors (drug abuse, suicide, etc). Frankly, the list is long and tragic. At least in the US, if you are under 18 years old you fall into the "pediatric" category of medicine and insurances will cover at least a portion of the cost, and you at least have some access to the mental health system. Once you turn 18, that "spigot" is turned off, that "kite string" has been cut. This is when tragedies become common.
There is almost no money to be made in mental health, as the majority of the patients tend to be of limited employment and carry little-to-no insurance. The mental health system, in many cases, eats the cost. As a result, people who work within that system, are also paid relatively poorly as compared to their peers in other areas of medicine. At the end of the day, you have to pay people, and if you are one to achieve an advanced degree, spend your time, money, and energy, accumulate a significant amount of education debt, you had better receive the types of salaries that can pay back that debt. It's basic economics from a professional standpoint. A young person going into medicine is going to direct their energies toward something that will not leave him/her decades of debt. The mental health system simply doesn't pay for the typical doctorate degree.
On the other hand, NOT having Federal tax dollars supporting the mental health system may be "shooting ourselves in the foot". Sure, up front, it costs money. However, are we simply swapping an up-front cost with a downstream cost? Do we spend $billions up front, or $billions on the back end dealing with the economic impact, policing crime, drugs, low-income housing, and a long, long, list of other things?
There was a time in the US when we took care of our citizens. Then, in 1981, all that changed with the Omnibus Budget Reconciliation Act, signed in 1981, by President Ronald Reagan.
Mental Health Systems Act of 1980 - Wikipedia. The Omnibus Budget Reconciliation Act of 1981
Omnibus Budget Reconciliation Act of 1981 - Wikipedia President Reagan was of the mind that less Federal government and more State and Local government was best. However, most, if not all, states did not have the budgets to support a mental health system.
The primary issue when it comes to governments, is simply political posturing. In summary, the Democrats tend to push for more Federal government oversight and management because the state and local governments typically never do. The Republicans want less Federal government oversight and management, and to push those responsibilities upon the state and local governments. The problem is this back-and-forth with each administration. Both Federal and State governments tend to be corrupt with huge bureaucracies, a lot of waste, fraud, and abuse. Privatization is on a profit-motive (money over people), less waste, but certainly at risk for fraud and abuse, which is never good when it comes to medicine and taking care of people. What can we do when both systems are bad in their own ways?