The trust, which runs East Surrey Hospital serving patients across Crawley and Horsham area, has been well above the threshold at which hospitals are deemed too busy constantly since the end of November.
NHS National Medical Director Professor Stephen Powis said: "While it is positive to see more NHS staff back at work, pressure on the NHS is still intense, having seen the busiest week for ambulances taking patients to A&E since the start of December – up almost 2,000 on the week before last – all while pushing to deliver as many routine checks and procedures as possible, including vital diagnostic checks.
“Our staff have already had what feels like a long winter, but despite everything they have had to contend with, they continue to step up as they always do; answering thousands more 111 calls last week than the seven days before, continuing to care for thousands of covid patients and maintaining non-covid procedures, and working closely with colleagues in social care to get people out of hospital safely.
“The public can help us by coming forward for their lifesaving covid vaccines, and as has been the case throughout the pandemic, if you have a health problem, please go to 111 online and call 999 when it is a life threatening condition – the NHS is here for you”.
The average general and acute bed occupancy at Surrey and Sussex Healthcare NHS Trust was 98.5% for the week from January 17-23 - the latest figures available.
The trust also reported that it was completely full at some stages during that week.
It has been 97% full or more almost constantly since November 29, only dipping slightly to 94% for the week covering Christmas.
NHS England says 85% occupancy of general and acute beds is the threshold at which hospitals are said to be too busy.
The latest data also shows that in the week from January 17-23 Surrey and Sussex Healthcare NHS Trust had 671 patients arrive by ambulance.
Of those the handover was delayed by 30-60 minutes in 60 cases.
Four cases had a handover delayed by more than 60 minutes.
In a table showing hospitals in England according to the percentage of ambulance handovers delayed by more than 30 minutes, the trust was ranked number 84 - with number 1 being the worst.