A record 7.6 million people in England were waiting for NHS treatment in June, with two in five patients waiting more than 18 weeks to be seen.
The figures come as junior doctors prepare to strike on Friday.
Nearly 400,000 people were waiting for treatment for heart conditions, the British Heart Foundation said, of whom more than a third (37%) had been waiting more than 18 weeks for care and a record 12,799 had been waiting more than a year for time-critical heart treatments.
There was an improvement in average ambulance response times for category 2 calls, which include suspected heart attacks and strokes. They fell to almost 32 minutes in July, from around 37 minutes in June.
However, once at hospital, just 61% of people were seen within the four-hour target in major A&Es in July, an improvement on the 50% low recorded in December, but still well short of the 95% target.
Key cancer targets also continue to be missed. Only 59% of patients started their first cancer treatment within two months of an urgent GP referral, well short of the 85% target. And only 62% of patients were seen within two months of a positive result from a national cancer screening test, compared with the 90% target.
The total number of people awaiting treatment, 7,574,649, is the highest figure recorded in the data series, which began in August 2007, and a rise of 1.4% on the previous high recorded in May this year (7,472,052).
In a statement, the NHS pointed to a reduction of 2,000 in the number of people waiting more than a year for treatment, despite three days of junior doctor strikes in June. According to NHS Providers figures, more than 835,000 operations and appointments have been delayed since December due to strikes.
Prof Julian Redhead, the national clinical director for urgent and emergency care, said there was “significant pressure on staff, with this summer currently on trajectory to be the busiest in NHS history, all while industrial action continues to disrupt services”.
“While tomorrow the NHS will see a fifth round of junior doctor strike action with thousands of appointments and procedures likely to be postponed, the NHS will need to prioritise emergency care once again,” he said, urging patients to continue to use 999 for life-threatening emergencies and 111 online for other health concerns.
Saffron Cordery, the deputy chief executive of NHS Providers, said the mounting backlog was caused by “a perfect storm” of squeezed funding, the pandemic, the cost of living crisis, insufficient staff and industrial action. She called for more government investment and an end to the strikes.
“Trust leaders’ efforts to recover urgent and emergency care – and to bring down the waiting list – must be backed nationally with proper support. This includes better government funding in workforce and capital, including beds and vital equipment, and a solution for the challenges in social care,” she said.
“The strikes divert trusts’ resources from bearing down on backlogs to managing the disruption they cause. It’s vital the government and unions talk to find a resolution to the pay dispute. There can be no delay.”
Health sources predicted waiting lists would rise further. Rishi Sunak pledged in January that “lists will fall and people will get the care they need more quickly”.
Rosena Allin-Khan, the shadow minister for mental health, said the government was failing to tackle the problem.
“Rishi Sunak has no plan to turn this around, he only offers excuses. He blames hard-working doctors and nurses, yet he hasn’t lifted a finger to stop the strikes.”
Dr Sarah Scobie, the acting director of research at Nuffield Trust, said the record figures showed it would be a “bumpy and difficult road” for the government and NHS to bring patient waiting times down and that “the prime minister’s pledge to bring these down looks even more out of reach”.
“NHS staff are working flat out, and we are seeing more care being delivered in June, but the pace at which services can increase the number of patients they are seeing is not fast enough against ongoing demand. While new measures, like more community diagnostics centres and patient choice, are helpful, the underlying staff and resources to carry out the work can’t be rapidly ramped up overnight. Further strikes, including strikes by junior doctors, will also add to the pressure on services.”