The hospitals that 'never treat patients on time'
Nearly one in five local hospital services are consistently failing to hit any of their key waiting-time targets, BBC analysis shows.
Twenty-nine hospital trusts and boards out of 157 have not hit a single target for a whole year.
Northern Ireland is struggling the most - all five trusts have failed their key targets for A&E, cancer and routine operations every time in 2017-18.
Dame Donna Kinnair, of the Royal College of Nursing, said the NHS was going into the winter "on the back foot".
She said research by the RCN showed hospitals were facing a shortage of both beds and staff - with images of "patients waiting on trolleys in corridors" becoming all too common.
The health departments in each nation have said they are committed to improving waiting times. In Scotland and Wales, specific programmes have been launched to speed up progress.
Northern Ireland's Health and Social Care Board conceded "the waiting times experienced by many patients continue to be unacceptable".
The Department of Health and Social Care in England praised "hard-working staff" and said the extra money being provided to the health service in the coming years would put it on a "sustainable footing".
How quickly are patients meant to be seen?
It depends on where you live in the UK.
In each UK nation, patients are meant to be seen within four hours of arrival at A&E - and by seen, the NHS means either admitted into hospital for further treatment or treated and discharged.
For cancer, each nation expects patients to start their treatment within 62 days of an urgent referral, although there are differences in the way each nation measures that.
The biggest variation in the way performance is judged is seen in the waiting times for non-emergency treatments, such as knee and hip replacements.
In England and Scotland, patients are meant to be seen within 18 weeks, while in Wales it is 26 weeks.
Northern Ireland has a different system in that it only measures part of the patient's wait - once they are under the care of a hospital doctor rather than when they are referred by a GP. The expectation is that patients will have their treatment within 13 weeks once they have had all their tests and scans and doctors decide they do need treatment.
Is this as bad as it has ever been?
If you look at the picture on a national level - adding together all the individual hospital services - performance has sunk to its worst level in recent times.
Each part of the UK has missed all its three key NHS targets every month or quarter for more than a year - the first time this has happened.
The last time a target was met was in August 2017 in Scotland.
In Wales, none of its three key targets has been hit for at least five years.
It marks the worst sustained period of performance since targets started being introduced shortly after the turn of the century.
Chris Hopson, chief executive of NHS Providers, which represents managers, said the system was facing "significant strain".
Which hospitals are struggling the most?
In England, 16 hospital trusts out of 131 missed all their monthly targets. They were:
- Bradford Teaching Hospitals
- Taunton and Somerset
- Guy's and St Thomas'
- Northern Lincolnshire & Goole
- Plymouth Hospitals
- The Royal Wolverhampton
- Mid Essex Hospital Services
- Leeds Teaching Hospitals
- University College London Hospitals
- East Kent Hospitals
- Hull and East Yorkshire Hospitals
- United Lincolnshire Hospitals
- Maidstone and Tunbridge Wells
- East and North Hertfordshire
- Worcestershire Acute Hospitals
- Brighton and Sussex University Hospitals
In Northern Ireland, all five trusts have failed to hit a single target in the past 12 months. They were:
- South Eastern
In Scotland, three out of 14 health boards missed all their targets. They were:
- Forth Valley
- Greater Glasgow and Clyde
In Wales, five out of seven health boards missed all their targets. They were:
- Cardiff and Vale
- Cwm Taf
- Aneurin Bevan
- Abertawe Bro Morgannwg
- Betsi Cadwaladr