New data has emerged showing that Covid infection levels have reached a new record high after a senior health official said findings that the Omicron variant is milder offer a “glimmer of Christmas hope”.

An estimated 1.7 million people in the UK had Covid-19 in the week ending December 19, the highest number since comparable figures began in autumn 2020, the Office for National Statistics (ONS) said.

The new interim data, published on Friday, also shows that around one in 35 people in private households in England had Covid-19 in the week to December 19 – up from one in 45 in the seven days to December 16.

This is the highest estimate for England since the ONS began estimating community infection levels for England in May 2020, and is equivalent to around 1.5 million people.

In London this rises to around one in 20 people likely to test positive for Covid-19, the highest proportion for any region in England, the ONS said.

North-east England had the lowest proportion, at around one in 55.

ONS chief Sir Ian Diamond said there were “some indications” of people engaging in “safer behaviour” in response to the Omicron wave.

But he told BBC Radio 4’s World At One programme: “At the moment I think it’s far too early to suggest that we will see anything other than a continued rise.”

Sir Ian said the “sobering” figures showed “really big increases” in Covid-19 cases, with London “clearly the epicentre of the Omicron epidemic” with numbers going up “really steeply”.

He added: “There are increases right across England, with the slight exception of the South West, increases in Wales and Northern Ireland, and Scotland has gone up just a little bit.”

The ONS also said that Covid infections compatible with the Omicron variant have increased in all regions in England with “substantial regional variation”, with the highest rates in London and the lowest in the North East.

In Wales, around one in 45 people is estimated to have had Covid-19 in the week to December 19, slightly below the record of one in 40 in October.

In Northern Ireland, the latest estimate is one in 40, equalling the record from mid-August, while for Scotland the latest estimate is one in 65, below September’s peak of one in 45.

The Government confirmed that a further 122,186 lab-confirmed Covid-19 cases had been recorded in the UK as of 9am on Friday, another new record for daily reported cases.

Meanwhile, the UK Health Security Agency (UKHSA) said there had been 23,719 additional confirmed cases of the Omicron variant reported across the UK, bringing the total to 114,625.

The number of deaths in England of people with the Omicron variant has risen to 29, and hospital admissions in England for people with confirmed or suspected Omicron rose to 366.

The latest figures come after UKHSA chief executive, Dr Jenny Harries, said data suggesting Omicron may be less likely to lead to serious illness than the Delta variant of coronavirus offers a “glimmer of Christmas hope”.

But she warned that it is too early to downgrade the threat from the new strain, which is still spreading rapidly across the UK.

She added: “There is a glimmer of Christmas hope in the findings that we published yesterday, but it definitely isn’t yet at the point where we could downgrade that serious threat.”

Dr Harries told BBC Radio 4’s Today programme that more information is needed, particularly about the impact on elderly and more vulnerable patients.

The UKHSA estimates that someone with Omicron is between 31% and 45% less likely to attend A&E and 50% to 70% less likely to be admitted to hospital than an individual with the Delta variant.

The rapid spread of Omicron has seen it become the “dominant strain now right across the UK”, and Dr Harries said cases are still doubling across “most regions” of the country.

Dr Harries added: “What we have got now is a really fine balance between something that looks like a lower risk of hospitalisation – which is great news – but equally a highly transmissible variant and one that we know evades some of our immune defences, so it is a very balanced position.”

The UKHSA data has fuelled speculation in Westminster that further restrictions can be avoided in England after Christmas.

In Scotland, nightclubs will close for at least three weeks from December 27 as part of a package of measures to control the spread of the virus, while clubs in Wales and Northern Ireland will close from Boxing Day.

But in England, the Government may choose to issue new guidance on limiting contacts rather than risk another damaging Tory rebellion by recalling Parliament to impose new rules.

Dr Harries said key pieces of information about Omicron are still needed to understand how much of a risk it poses to the health service, such as average length of stay in hospital.

But if the severity of the disease is actually “significantly lower than Delta”, then some of the impact on the NHS may be less severe, she said.

Dr Harries also suggested the Government might consider whether new restrictions are needed in England based on the wider impact of the Omicron wave, rather than just the severity of the illness.

Prime Minister Boris Johnson has not imposed any further restrictions for England over Christmas, but has indicated he will not hesitate to act afterwards – with Monday expected to be the first opportunity to consider if changes are needed.

Asked whether the Government will have the information on Monday to make key decisions, Dr Harries said: “Ministers will look at all of the data that we have available and that isn’t simply what the epidemiology is saying, it’s how it’s impacting society.

“So, for example, we have very high rates of individuals off sick – we know that particularly in London, around one in 35 have currently got Omicron.

“Now that’s having an impact on the workforce. So these are not simply about hospitalisation rates.”

She added that ministers are being kept updated on a daily basis and that will continue throughout the Christmas period.

Her comments came after Mr Johnson used his Christmas message to urge people to come forward to get a Covid booster jab as part of the “neighbourly” spirit of the season.

In Scotland, First Minister Nicola Sturgeon also used her Christmas message to urge people to get vaccinated, while in Northern Ireland, DUP leader Sir Jeffrey Donaldson said that Covid “should not be underestimated” as he isolates with the infection.

The UKHSA has emphasised that its findings regarding the severity of Omicron are “preliminary and highly uncertain” because of the small numbers of confirmed cases currently in hospital.

In its analysis, the agency also found around one in 10 new cases of the Omicron variant of coronavirus identified in England have been linked with a previous infection of Covid-19.

Vaccination is also believed to give less protection against Omicron, although a booster jab provides more protection against symptomatic disease compared with the first two doses alone.

Data suggests protection starts to wane 10 weeks after booster vaccination, the agency said.