Accident and Emergency has become a totemic service in the eyes of the public. It represents for many the essence of the NHS: free at the point of use, open 24 hours and caring for all in need.
Because of this, the target that 95 per cent of patients should be admitted to hospital or sent home within four hours of arriving at an A&E department has assumed huge political significance. This is even more so given that we are just two months away from a General Election.
At the start of the year it was, unsurprisingly, big news that A&E performance against this target dropped to its lowest level for a decade. Newspaper headlines screamed of a 'crisis' in A&E, proclaiming 'our NHS is dying' and decrying a 'Third World A&E'.
Since then performance against this measure has picked up slightly, although A&E is still under immense pressure: new figures published today show that the 95 per cent target has been missed for a further week, meaning it hasn't been met at major A&E departments since the summer of 2013.
Hospitals have been pulling out all the stops. But the system is near breaking point: the numbers of people waiting on trolleys for over four hours has almost trebled since 2010, and delayed ambulance handovers have grown by almost 70 per cent.
What's behind the A&E 'crisis'?
The reasons behind the problems in A&E are complex and not well understood. As the Nuffield Trust sets out in a new briefing published today, common claims - the impact of NHS 111 services or changes to out-of-hours services through Labour's 2004 GP contract, for example - are not borne out by the evidence.
The ageing and growing population is almost certainly part of the answer. People are living longer, with more complex conditions, sometimes needing longer spells in hospital or more specialist care. But these changes have been happening for many years, whereas the recent decline in performance started in 2012.
The reason A&Es are under so much pressure right now may be as much to do with the 'back door' of emergency departments as the 'front door. The lack of inpatient beds backs up through hospital and slows down A&E.
This may be because social care services can't be found to accommodate people, due to cuts to social services. Or it could be because care home beds are closing. Or it may be because of internal problems within the hospital caused by staff shortages or issues about how discharges are planned. Getting patients assessed for nursing home or other types of care can also take a long time.
The result is that hospitals become clogged up with people needing to be discharged but with nowhere to go. This has an effect a bit like a long queue on a motorway, with the nearest exit suddenly closed and drivers having to grind to a halt.
In previous winters, A&E departments have also come under severe pressure and performance has dipped. But the difference this time is that the problems don't appear to have been caused by an outbreak of flu or by managers taking their eye off the ball.
There's no one neat solution
The complexity of the issues facing A&E departments means there is no one neat solution. This is a problem for politicians, who perhaps understandably wish to solve the problem through pledges that will win them votes at the ballot boxes.
What is most worrying is that the political frenzy around the four-hour target seems to be combining with the financial strain facing hospitals to create an unhelpful and punitive reporting culture in the NHS, with staff spending disproportionate amounts of time reporting upwards to regulators and commissioners.
To tackle complex problems like those facing A&E departments, staff need time to think about how their services could be changed and the head room to experiment with new services. And the NHS needs leaders who can support and help the system adapt to the complexities of an ageing population.
Relegating the four-hour target
We have become fixated with the four-hour target. But emergency departments record other important quality measures too - from average time to treatment to re-attendance rates after seven days. These can give us vital clues about patients' experiences at A&E which may be missed by focusing on one narrow metric.
Relegating the four-hour target in importance and looking across a richer set of indicators like these could be an important way forward. But doing this will mean moving away from the weekly fix of headlines about hospitals 'underperforming' or, alternatively, meeting the target. Are politicians brave enough to go cold turkey on the totemic four-hour A&E target?