England suffered the highest levels of excess deaths of any country in Europe over the first half of 2020, the Office for National Statistics has said.
But while England endured the largest overall increase in deaths, the report says Spain had the highest peak.
Prime Minister Boris Johnson reacted to the news by saying there had been a "massive success" in reducing deaths.
Scientists have said excess mortality figures are the most reliable measure of the relative impact of COVID-19.
This is because countries record their deaths differently and will not necessarily account for those caused indirectly by the pandemic, such as people who have died due to delayed access to healthcare.
The ONS report said: "While England did not have the highest peak mortality, it did have the longest continuous period of excess mortality of any country compared, resulting in England having the highest levels of excess mortality in Europe for the period as a whole."
By the week ending 29 May, the cumulative mortality rate in England was 7.55% higher than the average mortality rate in the period from 2015 to 2019.
Spain was ranked second at 6.65%, followed by Scotland (5.11%), Belgium (3.89%) and Wales (2.78%).
And by the week ending 12 June, England's cumulative mortality rate was 7.61% higher than the five-year average, which was the highest among 18 countries where data was available.
Edwin Morgan, from the ONS, said: "Due to the coronavirus pandemic, the first half of 2020 saw extraordinary increases in mortality rates across countries in Western Europe above the 2015 to 2019 average.
"The highest peak excess mortality at national level was in Spain, with some local areas in Northern Italy and Central Spain having excess mortality levels as high as 847.7% of the average.
"While none of the four UK nations had a peak mortality level as high as Spain or the worst-hit local areas of Spain and Italy, excess mortality was geographically widespread throughout the UK during the pandemic, whereas it was more geographically localised in most countries of Western Europe.
"Combined with the relatively slow downward 'tail' of the pandemic in the UK, this meant that by the end of May, England had seen the highest overall relative excess mortality out of all the European countries compared."
Mr Johnson, asked for his reaction to the news on a trip to north Yorkshire, said: "We mourn every loss of life that we've had throughout the coronavirus epidemic.
"We really owe it to them to continue our work in driving the virus down.
"Clearly this country has had a massive success now in reducing the numbers of those tragic deaths."
Jonathan Ashworth MP, Labour's shadow health secretary, described the news as "a devastating moment".
"Every life lost is a tragedy and leaves behind grieving families," he said.
"We can no longer hide from the fact the government has not handled this crisis well and needs to urgently learn lessons from its mistakes.
"Boris Johnson must now take responsibility for why we were so badly prepared. As we start to see a resurgence in other parts of the world, ministers need to urgently outline the steps they are taking to better protect people and save lives in the months ahead."
Among local authorities across the continent, Bergamo in northern Italy had the highest peak excess mortality of 847.7% in the week ending 20 March.
The highest peak in a UK local authority was Brent - at 357.5%, in the seven days up to 17 April.
Of major cities, Europe's highest peak excess mortality was in Madrid at 432.7% in the week ending 27 March - while Birmingham had the UK's highest at 249.7%, also in the week ending 17 April.
Sky News Economics Editor Ed Conway said: "The UK faced one of the worst periods of mortality of any European country during the COVID-19 outbreak, the figures from the ONS have confirmed.
"Its analysis found that both Spain and the UK faced a dramatic rise in deaths above the five-year average in the face of the pandemic.
"But while the outbreaks in most other countries were concentrated in particular regions, the UK had the most widespread of all the outbreaks, with deaths rising sharply across the country.
"The ONS said that the highest rates of excess mortality across Europe were to be found in areas in central Spain and northern Italy.
"In particular, England had the highest cumulative mortality of any country in Europe, though Spain had narrowly more than the UK as a whole.
"There is nothing very surprising in this latest data on mortality, but that doesn't make it any less depressing."