There have been another 7,143 cases of coronavirus reported in the UK in the last 24 hours – the biggest rise since the pandemic began.
71 coronavirus-related deaths have also been recorded – the highest number since 1 July.
The significant rise in COVID-19 cases comes after the number of positive tests fell at the weekend, with Monday's figure at 4,044 cases.
Historically, reported cases on Tuesdays tend to be higher, due to a weekend lag.
Analysis: This is a worrying direction of travel
By Laura Bundock, Sky correspondent
There's no doubt we are testing more, so more cases are being picked up.
Experts suggest around the peak of the pandemic there were probably 100,000 new infections every day, we just didn't have the testing in place to find them.
The latest figures don't come anywhere near this, but what is worrying is we know the ratio of positive results to the number of tests is also rising.
This is a concern because a rise in infections seems likely to lead to a rise in deaths.
This could well take time to happen. But already, over the last four weeks, we have started to see a rise in the number of reported deaths.
It's worth remembering, Tuesday figures tend to be higher because of a delay in recording over a weekend.
But overall there does appear to be an upward trend, and that is a worrying direction of travel.
Tuesday's 7,143 new cases is an increase of five-times more than it was four weeks ago, when 1,295 cases were reported.
The 71 deaths are a sharp rise on Tuesday last week, when 37 fatalities were recorded.
There are 2,049 coronavirus patients in hospital across the UK, up until the 27 September, a rise from 1,331 in the previous week.
There are 262 patients in ventilator beds.
The prime minister is expected to give an update on the outbreak on Wednesday from Downing Street, alongside Chief Medical Officer Professor Chris Whitty, and Chief Scientific Officer Sir Patrick Vallance, amid the recent increase in cases.
On Monday, the government announced that household mixing in the north east of England would be banned from Wednesday evening, after a surge in cases in the region.