The number of deaths in the UK accelerated at the beginning of January as the effects of December’s wave of coronavirus cases raised mortality to levels not seen since last spring, according to official figures released on Tuesday.

The Office for National Statistics said that 17,751 deaths were registered across England and Wales in the week ending January 8, the highest total since the final week of April last year.

The jump in mortality rates suggests that since the pandemic began, the UK’s total excess deaths — the number above the previous five-year average — has risen to well over 100,000, according to a Financial Times model that brings official figures, which have a two-week lag, up to date.

The government reported on Tuesday that another 1,610 people had died within 28 days of testing positive for Covid-19 — the highest daily figure since the pandemic began.

However, the figure is unlikely to be a genuine daily record because many people died at the peak of the first wave without being tested. Excess deaths, which measures the total number of fatalities compared with normal levels, is not dependent on the levels of testing and indicated more than 2,000 daily deaths in the UK last April.

The delay between infection with Covid-19 and death — typically about a month — means that the vaccination programme will not yet have an effect on mortality rates.

With the number of deaths still rising, even as infection rates decline and the vaccination rollout progresses rapidly, ministers have warned that relaxations in lockdown restrictions are unlikely in the short term.

Matt Hancock, health secretary, said on Monday that “we’ve got to watch the data,” before considering lifting strict rules on social distancing. “We’ve got to see the number of deaths coming down and sadly we haven’t seen that yet,” he said.

The UK has one of the highest rates of excess deaths in western Europe, alongside Spain, Italy and Belgium — although mortality rates in parts of South and Central America are significantly higher still.

Chart showing how excess deaths compare around the world since Covid outbreaks began

After the pandemic pushed death rates above the seasonal average in March last year, Britain experienced a sharp wave of excess fatalities in April and May, raising the total number to roughly 65,000. The increase has been slower during the second wave of coronavirus infections, with excess death registrations hitting 94,745 by the week ending January 8.

With those figures almost two weeks out of date, an FT model based on the relationship between excess deaths and the daily Covid-19 fatality announcements from the government, estimated that there have now been 106,300 excess deaths in the country since mid-March.

Column chart of UK deaths in excess of 5-year average showing UK excess deaths have topped 100,000 during the pandemic

Before the publishing of the ONS data, excess mortality in the second wave of the epidemic had been lower than the daily Covid-19 rates announced by the government. This was used by those critical of the government’s lockdown measures to justify loosening restrictions. But experts said the lower level of excess deaths was likely due to social distancing leading to a drop in mortality from other respiratory diseases.

“The anti-Covid measures have been enough to stop flu in its tracks,” said David Spiegelhalter, chair of the Winton Centre for Risk and Evidence Communication.

When looking at the lower levels of excess deaths in the autumn, “one reassuring interpretation is that the lockdown measures and disruption of the health services have not yet caused a notable increase in non-Covid fatalities”, Prof Spiegelhalter added.

However, the data released on Tuesday showed that excess death rates had risen to match the daily coronavirus death totals. Kevin McConway, emeritus professor of applied statistics at the Open University, described the latest figures as “grim, very grim” because they did not yet include data for the period in January when the daily Covid-19 death figures peaked.

With more than 6,000 fatalities mentioning Covid-19 on death certificates in the first week of January, Prof McConway added: “It’s absolutely clear that the untypically large numbers of deaths in that week are because of the pandemic.”

The ONS data confirmed that excess deaths have now risen to the level of the daily Covid-19 mortality totals and are still concentrated among the elderly.

Of the total 5,576 excess deaths in the first week of January, 1,166 were among those aged over 90. Almost 81 per cent of those who died were over 70, the group the government hope to have delivered a first vaccine dose to by the middle of February.

Bar chart of excess deaths by age (week ending Jan 8) showing excess deaths are concentrated among the oldest in the community

Another measure of the severity of the crisis has been the total number of death registrations mentioning Covid-19. These rose to exceed 99,000 by January 8, according to the latest figures.

The ONS data also show that health authorities have again struggled to keep coronavirus out of care homes, which was a particular weakness during the first wave of coronavirus infections.

Column chart of deaths of care home residents involving Covid-19 showing residents of care homes in England are once again dying of coronavirus

Data from the Care Quality Commission, which regulates the sector, showed that 1,717 care home residents died from Covid-19 in the second week of 2021, the highest weekly figure since mid-May last year.