The NHS has recorded its worst year on record for A&E waiting times, figures show.
Between April 2018 and March 2019, 88% of patients were treated or admitted within four hours, according to NHS England data.
This is down from 88.3% in 2017/18 and 89.1% in 2016/17 – and the lowest since figures were first collected in 2004.
However, the number of people seen in A&E within the four-hour target was higher last year than ever before.
More than 21,800,000 people who attended emergency departments were seen within the target in 2018/19.
The data comes as the NHS prepares to pilot new targets which could lead to changes in the way A&E performance is measured.
Under the new plans, patients with the most serious conditions will receive rapid treatment within an hour, while people with minor conditions can expect to wait longer.
The proposals have faced criticism from some, who say targets are being abandoned because they can no longer be met.
Tim Gardner, senior policy fellow at the Health Foundation, warned that parts of the NHS are “creaking at the seams”.
“The record number of people treated within the four-hour target over the last 12 months is testament to the huge efforts of NHS staff,” he said.
“However growing numbers of people are waiting over four hours as demand continues to outstrip provision.
“It is becoming untenable for the NHS to maintain quality of care in the face of ever rising demand from patients with increasingly complex conditions, ongoing funding issues and growing staff shortages.
“As the NHS begins to test new waiting time targets for A&E to replace the four-hour standard, it is absolutely vital that comparable data remains publicly available to maintain a consistent, long-term view of how the NHS is performing in the face of these pressures.”
In March, 86.6% of patients were seen within four hours at A&E, the NHS England data shows, meaning more than 290,000 waited longer than they should have.
This has risen from 84.2% in February, which was the lowest monthly performance recorded in 15 years.
The 95% standard has not been met since July 2015.
Dr Nick Scriven, president of the Society for Acute Medicine, said: “This has been and continues to be an extremely challenging time for urgent care in the NHS which has been overlooked amid the chaos of Brexit and the smokescreen it has created.
“My major imminent concern is that hospitals are working flat out at the moment and we have a looming spell of bank holidays when many support services will not be functioning, heaping up the already relentless pressure.”
NHS England said more than seven million patients were seen within four hours between December and the end of March, the highest on record and 380,000 more than last year.
Pauline Philip, national director of emergency and elective care, said: “Throughout the NHS, staff have worked tirelessly to deliver the improvements we’ve seen for patients this winter, putting in place new and improved services, delivering a record number of flu jabs and providing care directly to a record number of people.
“Millions of people in England who have benefited from NHS care and advice this last few months will therefore want to join me in paying thanks to all health service staff for their exceptional efforts.”