More people waited over 12 hours at A&E in Stepping Hill hospital last month than anywhere else in the country.
National data also places the Stockport hospital as fifth from worst nationally for four-hour wait breaches, with exactly a third of patients waiting longer than that to be seen.
Apart from the Royal Bolton, figures show all Greater Manchester's other hospitals were well above average in terms of performance, in a month that saw the worst national figures on record.
But Stepping Hill's performance indicates it is struggling. It was one of 60 hospitals to see patients wait longer than 12 hours, which is not supposed to happen in any department.
In most of those cases, however, only a handful of patients were affected - while in Stepping Hill, 63 people ended up in that position.
Targets brought in by New Labour are supposed to see 95pc of patients seen within four hours, although that national target has been missed consistently since 2015.
October saw the worst national figure on record, at 74.5pc.
In Stockport just 67pc of people were seen in that time, however, with only four hospitals in Birmingham, Lincolnshire, Shrewsbury and Norfolk performing worse. At the Royal Bolton, the figure was 70pc.
Stepping Hill’s A&E has struggled for years, with insiders blaming a mixture of the ageing estate, funding problems, high pressure on the borough’s social care market and tensions between local health and social care organisations.
This is not the first time the hospital has been bottom of the national league table for waiting times, but despite interventions by local and Greater Manchester-level officials, the problem has not gone away.
In a statement, Stockport NHS Foundation Trust acknowledged the unit was under continuous strain.
“We are experiencing long term heavy pressures in our A&E emergency department, and these are having an ongoing impact on our waiting times,” said a spokesman.
“We serve an area with a population that has a high portion of older people, who are often frail with complex conditions, and they place a particular demand on our emergency services.
“We always prioritise our most urgent cases, and when patients who need to be admitted to hospital are described as ‘waiting’ in the A&E department they are still receiving the safe care and necessary treatment that they need.
“Our staff work tirelessly in very busy conditions to ensure that the people who need our support receive good quality care.
“We are continuing to work closely with colleagues across the health and care system in Stockport on longer term solutions to the pressures our services face, and the public can help by only visiting our A&E if it is a genuine emergency.”
The M.E.N. reported earlier this year on tensions between the hospital trust, local clinical commissioners and Stockport council, whose plan to pool resources in the long-term had been ditched abruptly amid disagreement.
Stepping Hill also serves several battleground seats in the current general election, prompting the Liberal Democrats in High Peak - just outside Stockport - to blast the Conservatives.
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"It is shameful that patients in High Peak are being abandoned, be it waiting for hours for treatment in A&E or for months in pain for routine operations,” said candidate David Lomax.
"These figures reveal the Conservatives' dismal record on the NHS. For the past four years the Tories have utterly failed to invest properly in our health service, leaving local hospitals underfunded, overstretched and understaffed.”
The Conservative Party was approached for comment on Stepping Hill’s performance earlier today, but did not respond.