Northern Ireland has overtaken England to become the UK nation with the highest rate of new coronavirus cases.
It is also the only one of the four nations that is recording a steady rise in rates.
A total of 9,832 new cases of Covid-19 were recorded in Northern Ireland in the seven days to July 21 — the equivalent of 519.2 cases per 100,000 people.
This is up sharply from 253.4 one week earlier and is the highest rate for Northern Ireland since January 9, according to analysis by the Press Association.
By contrast, England now has the second highest rate of the four UK nations and is sitting just behind Northern Ireland on 499.1 cases per 100,000 people.
While this is up week-on-week, the figure is slightly below the rates recorded for England in recent days.
Wales is also starting to show a drop in rates, with a figure of 184.1 cases per 100,000 people for the seven days to July 21 — down from 192.8 one week earlier.
The rate for Scotland has been falling steadily for the past few weeks, and stands at 215.3, down from a peak of 427.3 on July 3.
The fall in rates that is now under way in three of the four nations reflects the recent drop in the daily number of new reported cases for the whole of the UK.
But the ongoing rise in rates in Northern Ireland is a reminder that the UK-wide figures can conceal variations between different nations.
Every local authority area in Northern Ireland is now recording a week-on-week rise in rates.
In Scotland only six of the 32 local areas are recording a rise, however.
And in Wales, only eight of the 22 local areas have seen rates increase week-on-week.
Of the 315 local authority areas in England, 270 (86%) are still showing a week-on-week rise in rates.
This is because the fall in cases reported in recent days has yet to show up in the weekly figures.
Most regions of England are also still recording a week-on-week increase in rates.
The one exception is north-east England, where the rate stood at 804.5 cases per 100,000 people for the seven days to July 21.
This is down from 910.4 one week earlier.
North-east England continues to be the main regional hotspot of the current wave of coronavirus, with Redcar & Cleveland, Middlesbrough and Stockton-on-Tees recording the highest local rates in the UK.
Yorkshire & the Humber has the second highest regional rate in England (589.8), followed by north-west England (545.0) and the West Midlands (511.0).
South-east England has the lowest rate: 417.8.
All rates are based on the latest data published by the UK's health agencies.
Meanwhile, newly reported Covid-19 cases in the UK have fallen for the sixth day in a row but the number of patients in hospital with the disease in England has reached its highest level since mid-March, official data shows.
The Government said that as of 9am on Monday, the UK recorded a further 24,950 lab-confirmed Covid-19 cases, down from the 46,558 on July 20.
Dr Mike Tildesley, an infectious diseases expert, said the closure of schools for the summer break was likely to be one of the reasons for falling case numbers, but that it was too soon for data to show any effect from England's easing of restrictions on July 19.
Meanwhile, the NHS said yesterday that a total of 5,055 patients were in hospital with Covid-19 in England, up 33% from the previous week and the highest level since March 18.
The figures reflect the impact of the third wave of coronavirus that began at the end of May.
Dr Tildesley, a member of the Scientific Pandemic Influenza Modelling group (Spi-M) advising ministers, said it always takes a couple of weeks for case numbers in the community to be reflected in hospital admissions
He explained that the time lag between infections and hospital admissions means that admissions are likely to continue to rise in the coming days regardless of the number of cases.
Dr Tildesley, from the University of Warwick, said he is "cautiously optimistic" about the drop in cases but only time will tell if the third Covid wave is "turning round".
He told BBC Radio 4's Today programme that "any situation where cases are falling clearly is good news".