The performance gap between the NHS in England and in Scotland, Wales and Northern Ireland has narrowed, a new assessment of the quality of patient care in all four UK countries since devolution finds.

There have been significant improvements in health service performance across all four countries, with particular progress linked to tougher sanctions and targets in Scotland, although waiting times in Wales have risen as austerity sets in, says the report, from the Nuffield Trust and the Health Foundation.

No one country is now emerging as a consistent front-runner in terms of performance, is despite “hotly-contested” policy differences between each country, such as England’s greater emphasis on patient choice and the use of private-sector providers, and the rejection of competition in Northern Ireland, Scotland and Wales.

On health care spending, the study finds that all four nations have increased their investments, doubling in cash terms the amount spent on healthcare across the UK between 2000/1 and 2012/13, and investing in more staff.

But there have been divergent spending decisions, with Scotland spending almost £900 million from the money notionally available for health on other services or on making existing services free of change, including free personal care for older people. And Wales has spent around £450 million on other services.

Spending across the board has slowed in response to austerity, the study adds. Over the three years from 2010/11 to 2012/13, annual rates of change have been: up 2% in Northern Ireland; up 1% in England and Scotland; and down 1% in Wales.

Since a previous study, conducted by the Trust in 2010 using data up to 2006/7, England has been performing marginally better across a number of key indicators, including amenable mortality rates, life expectancy and ambulance response times. However, the gap has narrowed on many indicators, and differences between the countries are often small, it says.

Scotland shows a marked upturn in performance on indicators associated with targets and performance management - such as waiting times for planned surgery, which now broadly match England’s - and ambulance response times.

Wales is demonstrating improved performance on a number of indicators but deteriorating performance on waiting times since 2010, with striking rises in waits for common procedures. For example, in 2012/13 a typical Welsh patient waited about 170 days for a hip or knee replacement, compared to about 70 in England and Scotland.

And Northern Ireland has improved its performance on most indicators, although MRSA mortality rates remain higher than in both England and Wales.

The report also analyses the North East of England as a comparator to the devolved countries, because it shares many characteristics with them. Among the most notable findings are that the North East has benefited from higher investment than the average for England, and now spends similar amounts to Scotland, at £2,150 per head in 2012/13 compared to £2,115 in Scotland, while the English average was £1,912.

The North East also saw marked improvements during the 2000s in treatment rates, hospital staffing, mortality rates and life expectancy. In the 1990s, its overall mortality rates were similar to Scotland’s, but by 2010 these rates were 15%-19% higher in Scotland than in the North East. The region had similar life expectancy to Scotland in 1991, but by 2011 men and women there were living a year longer than those in Scotland.

Commenting on the latter findings, Andy McKeon, senior policy fellow at the Nuffield Trust, said: “the North East’s remarkable progress on reducing avoidable deaths and improving life expectancy suggests that local conditions, such as funding and the quality of staff, are to real determinants of health service performance.”

Health Foundation chief executive Jennifer Dixon added that it was “humbling for politicians that so far no one policy cocktail seems to be more effective than another on NHS performance,” and that this was “despite all the rhetoric” about the benefits or otherwise of introducing competition among providers.

“Supporting local clinical teams is likely to be the best long-term strategy to improve the quality of care,” she added.