To suggest that an ageing population is the biggest stress on the NHS is an oversimplification in my view. The biggest issue is that the NHS provides care far beyond what was possible when it was founded. I can remember when MRI scanners could be counted on your thumbs, when heart transplants always made the headlines, when a hip replacement was science fiction. These things and so much more are routine now, but still bloody expensive. People expect them, demand them, but are reluctant to accept that if they want them to continue, while the NHS also continues to provide GPs, dentists, maternity services, nursing care and all the other services it was set up to provide, they are going to have to pay more in tax, or pay for private medical insurance. I would prefer more tax, I could afford to go private but would rather pay that extra into the general pot so everyone benefits, not just me and some revolting insurancemonger.
We pay a sort of crinkly tax here on top of normal tax to cover retirement, care home etc