The Royal Free has restricted staff holiday and cancelled some non-urgent procedures as staff fight the second surge of Covid-19 infections.
As hospitals across the capital come under increased pressure, the rise in cases in Camden was described as "alarming" by one GP.
The latest government data shows 35 Covid patients were admitted across the three hospitals of the Royal Free NHS Trust on December 20, by far the highest figure since mid-April.
The figures show there were 244 Covid patients in the trust's hospitals as of December 23, with 78 at the Whittington.
A Royal Free spokesperson said: "Like all acute trusts in London, we are experiencing an increase in the number of patients with Covid-19 being admitted to our hospitals.
"As part of our plans to manage a second surge, we have postponed some non-urgent appointments and procedures. Annual leave for staff has been limited to ensure our hospitals are safe.
"We would like to thank our staff for their incredible commitment at this very challenging time."
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It is understood that non-urgent surgery is now at a minimum, and staff have been told to limit holiday to five days — including bank holidays — between December 21 and mid-February.
A consultant at the hospital told this paper: "Although we're not at quite the same Covid peaks we saw back in April, overall things are very busy and very tight here as we have the usual increased pressures on the ED (emergency department) and beds that we see every winter now, on top of the Covid surge."
New cases in Camden, Haringey and Barnet are all continuing to rise. Government data shows that on December 29 Barnet had 753 positive cases reported, with 476 in Haringey and 315 in Camden.
Camden GP Dr Daniel Beck, of the Swiss Cottage Surgery, said he had seen positive Covid test results in his patients rise rapidly in the last month.
He said: "In North Central London, and within my practice, we have seen an increase. I have seen a spike in new cases coming back in the last two weeks. On December 3 we had 10 positive Covid cases that week, today had 61 in the last week. That's alarming to me."
The Royal Free has been operating as a vaccine hub since early December, and now the Whittington has also been given vaccines to offer local people.
READ MORE: England star Daybell works on Whittington ward during the pandemic
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