Labour’s deputy leader Angela Rayner has said the UK is facing the prospect of another national lockdown because of Boris Johnson's "failure and incompetence".
Health secretary Matt Hancock has warned the UK is at a “tipping point” in the fight against coronavirus.
He has urged the public to follow strict rules across the country or face further restrictions.
Londoners could be told to work from home as early as this week as ministers battle to get the number of cases under control, he indicated.
Labour has accused the government of incompetence over its under fire NHS Test and Trace system, after thousands struggled to get a test last week.
In speech at Labour’s ‘virtual’ conference, Ms Rayner said: "We are facing a second spike (in Covid-19), further restrictions and the prospect of another national lockdown because of ( Mr Johnson’s) failure and incompetence."
She also accused the prime minister of a need to blame others for his government's failings.
She said: “It is always somebody else's fault - civil servants, the public health body they voted to create in the first place, or even the public for doing the right thing and trying to get a Covid test."
Ms Rayner also warned that the upcoming end of the government furlough scheme could leave the UK one step away from mass unemployment.
Labour is urging the government to bring in new measures when ministers stop paying the wages of millions of Britons at the end of October.
Ms Rayner said: “If the government ends the furlough scheme with no support in place for the sectors and areas that need it then workers and employers alike face a cliff edge, with mass unemployment just one step away.”