On Wednesday, Professor Chris Whitty appeared at a press conference with Prime Minister Boris Johnson at 10 Downing Street.
They warned of a "serious threat" and that the British will have a bitter Christmas.
It is estimated that about one million Britons are isolated because they tested positive for covid-19.
- I fear an increased number of omicron patients who will be admitted to hospital.
It is difficult to give exact numbers, but it will be high numbers and it will be clear shortly after Christmas, said Professor Chris Whitty and added that this year's Christmas will still be better than last year's.
78,000 new cases
The previous British record was recorded in January 2021 when just over 68,000 infected people were reported in one day.
On Wednesday, about 10,000 more cases were noted.
It occurs when 81.5 percent of the population aged 12 and up received the second dose of vaccine, according to the British government's database.
43 percent of the population aged 12 and older received a third dose or so-called "booster dose".
- I will not change our policy, Johnson stated with the sign "get boosted now" on his podium, a call to the public to continue vaccinating themselves.
All Britons over the age of 18 can book a third dose of vaccine.
Bookings can be made two months after the second dose.
People in the risk group are encouraged to take a fourth dose.
"Incredibly fast"
The British are also preparing for mass testing.
From Saturday, Royal Mail will be able to deliver twice as many home tests by post - around 900,000 tests every day.
Concerns about omikron are great.
- It is spreading insanely fast, in a way we have never seen before, a doubling happens every other to every third day, said Health Minister Sajid Javid to British media on Monday.
Hospital admissions due to covid have increased by ten percent in one week in the country.