Older people recall when the National Health Service was the flagship of the UK's welfare state. Many Irish people have been employees or patients of it. There are close professional links between the two states.
But today, some defenders of the Republic's two-tier system cite the failures of the NHS as evidence that comprehensive, equitable systems don't work. Such comparisons ignore the successes of the NHS, its underfunding by European standards and its mutation under Conservative governments, not to mention the relative success of comprehensive, equitable systems elsewhere.
Founded in 1948, the NHS will be forever associated with Aneurin Bevan, the combative Labour minister for health who battled the medical profession to establish it. He set up the NHS to provide comprehensive, universal access to healthcare based on need rather than ability to pay.
The overwhelming majority of services remains free at the point of use. The UK funds NHS care from general taxation rather than from social insurance, as in Germany. Successive opinion polls have shown a strong attachment to the NHS.
Since 1999, however, even the Republic has been spending more than the UK per capita on healthcare. Both states have spent less than the EU average for decades, the UK since 1970. The Republic's health spending last year, finally, reached the EU average.
While Tony Blair has pledged to increase NHS funding to the same level, commentators question whether planned increases will achieve that.
The Republic and the UK are now relatively equal in wealth. The Republic's GDP per capita exceeds that of the UK, but the better measure of Irish income, GNP per capita, was last year just above the EU average and close to UK income.
Many in the UK believed the myth that the NHS provided better healthcare more cheaply than the "Continentals". But as Jeremy Laurance, health editor of the London Independent, confessed last year: "How wrong I was . . . The gap between the standard of service for Dutch, German, French, American and New Zealand patients and that offered by our NHS is so glaring something has to be done . . . It will take decades of spending at levels beyond anything ministers have contemplated to bring us to their standard of provision."
Alan Milburn, the UK health secretary, has publicly supported the introduction of an earmarked health tax linked to better services.
Life expectancy for men and women in the UK is greater than that in the Republic, but it barely exceeds the EU average for men. Waiting lists are controversial but generally compare favourably with those in the Republic. This summer, only 286 patients had waited more than 18 months for surgery in England. Northern Ireland waiting lists are worse than the Republic's, however. The UK has fewer acute beds (2.4 per 1,000 people) than the Republic (three per 1,000 people).
NHS hospitals are owned by the state, and hospital doctors are salaried. Consultants' pay ranges from £50,800 sterling (£63,920) to £128,900 sterling (£162,025), compared with £87,000-£113,000 for consultants' public-hospital contracts in the Republic.
Most NHS consultants - 58 per cent - are full-time and may not earn more than 10 per cent of their gross income from private practice; nearly 90 per cent of consultants in the Republic opt for the lower end of the public pay scale, which they receive for a 33-hour week, with the potential for unlimited private earnings.
There are fears that private earnings might reduce commitment to NHS work, but a 1992 survey reported that full-time consultants spent a mean of 53 hours a week on NHS work and six on private work. Private-practice earnings for full- and part-time consultants averaged £27,000 sterling (£33,975), with the majority earning much less. GPs work for the NHS on contract and earn an average of £55,000 sterling (£69,210) after expenses.
For the patient, most healthcare is free. Charges for drugs, dentistry and optical care do not apply to children, the poor, the elderly or the sick.
The UK has 230 private hospitals, predominantly for-profit. Their most common procedure is abortion (13 per cent), followed by straightforward elective surgery. Some 10 to 11 per cent of the population has private health insurance, which may buy more rapid but not necessarily better care.
As prime minister, Margaret Thatcher introduced tax relief on private health insurance for the over-60s and allowed private hospitals to compete to deliver services to NHS patients.
The Blair government opposes greater use of private medical insurance but, controversially, supports private provision of hospitals for leaseback to the NHS.
The Conservatives attempted to introduce markets by letting local health authorities and GP practices become "fundholders" who could buy services for their patients from hospitals and other community-health "providers". Some hospitals closed because they lost contracts. As some GPs were fundholders and others not, inequities in access emerged.
Labour abolished GP fundholding on entering office. It has retained a distinction between purchasers and providers, but relations are more collaborative than competitive. GPs are members of primary-care groups, whose functions may evolve from advising on local health needs to commissioning care.
Health policy has now been devolved to the regions and is increasingly divergent - GP fundholding will be abolished in Northern Ireland only next April.