It comes as nurses admitted there is "barely a spare bed" in the entire health service, with health leaders sounding the alarm hospitals are "busier than ever" for this time of year, entering a winter they are "desperately worried" about.
NHS England figures show an average of 517 beds at Royal United Hospitals Bath NHS Foundation Trust were occupied each day in the week to December 1.
It means around 98% of beds at the trust were occupied last week – up from 96% the year before, and the highest proportion for this time of year since 2020-21.
The figures exclude 2021-22 as comparable figures were not provided.
Nationally, 96,587 hospital beds were occupied each day last week – more than have been recorded at this point in any other year.
It means that around 95% of hospital beds in England are full.
The Government published its Plan for Change this week, which aims for 92% of patients needing planned treatment to be seen within 18 weeks.
In a speech setting out the plan, Sir Keir Starmer said the NHS is "on its knees" and that meeting the waiting time target would show the service is "back on its feet".
Patricia Marquis, executive director for England for the Royal College of Nursing, said: "There is barely a spare bed in our NHS, with sky-high flu admissions and thousands stuck in hospital unable to be discharged due to a lack of capacity in social care.
"Before the cold weather hits, nursing staff and patients are desperately worried about what the coming weeks and months may bring."
NHS national medical director Professor Sir Stephen Powis said the NHS is "busier than ever", warning of a "quad-demic" with rising hospital admissions for flu, Covid, respiratory syncytial virus (RSV) and norovirus.
The figures also show an average of 1,098 flu patients were in hospital beds nationally each day last week, including 39 in critical care.
This is up sharply on the equivalent numbers for the same week in 2023, when the total was 221 with nine in critical care.
However, none of these were at Royal United Hospitals Bath.
Meanwhile, norovirus cases have risen by 86% nationally year-on-year, with an average of 756 patients with norovirus in hospital each day last week.
A further 1,390 patients were in hospital with Covid, and 142 children with RSV.
Professor Powis said: "The NHS is busier than it has ever been before heading into winter, with flu and norovirus numbers in hospital rising sharply – and we are still only at the start of December, so we expect pressure to increase and there is a long winter ahead of us."
Professor Susan Hopkins, chief medical adviser at the UK Health Security Agency, added: "It’s clear that unless more eligible people come forward to receive their flu vaccine, we are likely to see more cases of flu, and more hospitalisations and deaths, than we saw last year.
"It is still early in the season, so there is still time to change the trajectory and reduce the impact of flu in our communities in time for Christmas, but time is running out."