Nearly one in five NHS hospital services have failed to hit any key national waiting-time targets in the last year, analysis shows.
An investigation by the BBC found that 29 hospital trusts and boards out of 157 across the UK had not hit a single target for a year.
Northern Ireland was the worst performing with all five of its trusts failing their A&E, cancer and routine operations targets every month in 2017/18.
The BBC found that England, Scotland, Wales and Northern Ireland each failed to achieve the targets for the first time since they were introduced more than a decade ago.
The last time any target was met on a national level was in August 2017 in Scotland, while Wales has met none of its three key targets for at least five years.
NHS Providers chief executive Chris Hopson warned the coming winter is expected to be even more challenging than last year.
He added: "The pressure on A&E services and the knock-on impact this is having in other parts of the health and care system, coupled with higher levels of staff vacancies, will put services under significant strain this winter.
"If NHS trusts are to recover their performance against key targets, we must be realistic about the time and resources this will take, and how much of a focus this should have against competing priorities within the long-term plan."
NHS leaders said the service was facing a difficult winter, but stressed demand was much higher than last year.
The Department of Health and Social Care said there were 840,000 more A&E attendances in England in the last 12 months compared with the previous year.
A spokesman said the £20.5 billion by 2023/24 promised in the Budget will improve frontline services.
He added: "Despite an extra 840,000 people going to A&E, hardworking NHS staff have seen nearly half a million more people within four hours over the last 12 months than compared to last year.
"We have given the NHS £1.6 billion this year to improve performance and cut waiting times, as well as £420 million in additional winter support to redevelop A&Es, improve emergency care and help patients get home quicker."
The BBC analysis found that 16 out of 131 NHS trusts in England missed all three of the key national targets, while all five in Northern Ireland failed to achieve the standards.
Three out of Scotland's 14 health boards and five of Wales's seven boards failed to hit any of the three standards.
Patients are meant to be seen within four hours of arrival at A&E and either admitted to hospital or treated and discharged.
While cancer patients in every country are expected to start their treatment within 62 days of an urgent referral, there are differences in the way each nation measures that.
But there is more variance between expected waiting times for non-emergency treatments, such as knee and hip replacements, with patients in England and Scotland meant to be seen within 18 weeks compared with 26 weeks in Wales.
Northern Ireland only measures part of the patient's wait once they are under the care of a hospital doctor, which means any waiting for tests and scans is not counted in the 13-week target.
The 16 trusts in England that missed all the monthly targets:
- - 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
- - Belfast
- - South Eastern
- - Northern
- - Southern
- - Western
- - Forth Valley
- - Greater Glasgow and Clyde
- - Lothian
- - Cardiff and Vale
- - Cwm Taf
- - Aneurin Bevan
- - Abertawe Bro Morgannwg
- - Betsi Cadwaladr
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) Dominic Lipinski / PA Wire.