Something to consider for those who advocate government-run health care, it will be more of the same:

Three quarters of GPs who referred patients to hospital have had their decisions blocked, a poll for The Sunday Telegraph reveals.

Family doctors say that new “referral management” systems, set up to allow primary care trusts (PCTs) to overrule decisions taken in the surgery, are being used to delay and cancel hospital care, and to divert patients referred to a hospital consultant to cheaper clinics in the community.

Update –
Dr. RW correctly says that a single-payer system will just be managed care on a national level:

It’s ironic that the proponents of a national health care system in the U.S. try to bolster their arguments by citing the evils of managed care, that monster we all love to hate. But national health care, in whatever form it may ultimately arrive here will, likely as not, be a system of heavy managed care under multiple layers of intrusive government bureaucracy—everything we hate about managed care and much more.