The UK has recorded 23,511 new COVID-19 cases and 131 more coronavirus-related deaths in the latest 24-hour period, according to government data.
It is the seventh day in a row that the number of infections has fallen.
But it is the highest number of daily deaths since 17 March, when 141 fatalities were reported.
It takes the total number of people who have died in the UK within 28 days of a positive COVID test to 129,303.
Separate figures published by the Office for National Statistics (ONS) show that since the pandemic began there have been 154,000 deaths registered in the UK where coronavirus was mentioned on the death certificate.
Responding to Tuesday’s data, Dr Yvonne Doyle, medical director at Public Health England (PHE), said: “Rates are still high and the pandemic is not over yet, today we have recorded the highest number of deaths since March.
“This is in part due to the high number of cases recorded in recent weeks. We know deaths follow when there are a high number of cases and data today highlights we are still in the third wave.”
She continued: “We can all help. Meeting outside is safer than inside, get two doses of the vaccine as soon as you can and isolate if you are told to by NHS Test & Trace. If you show symptoms, stay home and get a PCR test. Limiting your contacts is the best way to stop the virus spreading.”
Today’s figures compare with 24,950 infections and 14 deaths reported yesterday, while 46,558 cases and 96 deaths were announced this time last week.
Also, 64,585 people had their first dose of a COVID vaccine yesterday, taking the total to 46,653,796.
And a further 171,676 people had their second jab, meaning 37,459,060 are now fully vaccinated.
The latest data has shown that England and Wales recorded the highest number of weekly coronavirus-related deaths since April.
There were 218 deaths with coronavirus mentioned on the death certificate in the week to 16 July, according to the Office for National Statistics (ONS) – the third consecutive weekly rise and a 19% increase on the previous seven days.
Speaking to reporters earlier, Boris Johnson acknowledged the falling case numbers over the past week.
He said: “I’ve noticed that, obviously, we are six days into some better figures.
“But it is very, very important that we don’t allow ourselves to run away with premature conclusions about this.
“Step four of the opening up only took place a few days ago; people have got to remain very cautious and that remains of the approach of the government.”
Earlier, policing minister Kit Malthouse told Sky News he thought the falling cases was an “interesting cocktail of effects” – and it seems to be a common theory in government that a number of factors are contributing to the decrease.
SAGE member Professor Mark Walport admitted “everyone’s scratching their heads a little bit as to exactly what the explanation is”, while other scientists have urged caution.
And Dr Duncan Robertson, an expert in COVID-19 modelling and analysis, said we should be looking at the positivity rate (or percentage of tests coming back positive) – which remains “very high” and could indicate not enough testing is being carried out.