EMERGENCY departments failed to see the target 90 per cent of patients within four hours last month, new figures show.
Only 88.9 per cent were seen, less than the 89.7 per cent in August and 89.7 per cent in September 2017.
The NHS England figures also showed its worst second quarter performance against the standard since records began in 2004/5.
Overall, the quarter's performance was 89.3 per cent compared to 90.1 per cent for the same period last year.
There was also further deterioration on 18 week elective referrals, which slumped to 87.2 in August against the 92 per cent target.
It was 89.4 in August 2017.
The data lays bare the dire state of NHS performance, as the Government considers a range of controversial measures to fund it's promise of £20.5 billion NHS funding growth over the next five years.
NHS Providers deputy chief executive Saffron Cordery, blamed rising A&E attendances.
She said: "These figures reflect once again the steep and relentless rise in the demand for care that trusts are facing, and the fact that this has become a year-round phenomenon.
“They also highlight the frustrating paradox of trusts and frontline staff pulling out all the stops to cope with growing pressures, but slipping further and further from the constitutional standards the public have been told to expect, and the recovery trajectory set out in NHS planning guidance.
“Waiting lists for operations continue to grow, but inevitably, attention will focus on performance in A&E where – compared with the previous September – the number of people coming in for help rose by over four per cent to more than two million.
“Alongside increased attendances we are seeing a growing proportion of patients having to be admitted as an emergency.
The total has risen by nearly five per cent in the last twelve months.
Yet again, NHS trusts have responded to the challenge.
MIND OVER MATTERWhat are the symptoms of anxiety, how can it be treated and who else suffers? From Zayn Malik to Will Young
'It's the worst case I've seen'Psoriasis sufferer's leg is left covered in agonising scales with chunks of skin flaking off
BOTCHED JOBFlat-chested mum is left with 'UDDERS for breasts' after forking out £11k on dream boob job that went horribly wrong
“The number of people admitted, transferred or discharged within four hours in September increased by more than three per cent compared with the same time last year.
But this wasn’t enough to keep pace with growing demand."
She said the country is facing challenges right across health and care, and the issue is not confined in hospitals.