The increasing demand is due to high birth rates in the 50s and 60s. Those people now are older, many are now passed working age.
The politicians of all parties have had almost 70 years in which to plan for this - and for most of the last 70 years, the government has been led by the Conservatives.
Despite their attempts to pretend that they inherited the issue from "someone else", the current government has been in power for 14 years. Someone now aged 66 was only 52 when this government came to power.
So what was the government's plan for addressing the issue of the increased need for healthcare? The longest-serving Health Minister that the country has ever had is one Jeremy Richard Streynsham Hunt, who was Minister for 6 years. His response to the looming, and entirely foreseeable, problem was to cut nursing training, reduce investment in the NHS and impose such a poor pay deal on the junior doctors (who today would be the senior doctors) that they left the NHS in droves and went to work in Australia, Canada and elsewhere.
This is the same Jeremy Hunt who is now Chancellor, who has told the NHS Trusts that they will have less money per capita (in real terms) than ever and that balancing the books is more important than treating patients.
Sunak is no better. He keeps trying to blame the huge waiting list on Covid. Other countries also had Covid. No country in Europe has 10% or more of the population waiting months for an NHS appointment. Even before Covid, waiting lists doubled from when the Conservatives came to power, and the lists doubled again after Covid. Last night he tried to blame the nurses - the nurses who are taking industrial action (or even worse, leaving the NHS) because of the appalling working conditions that they are forced to work under because of years of under-investment and the downright incompetence of successive ministers.