Boris Johnson has apologised to businesses for the "nightmare" Covid situation and vowed that England's second national lockdown will last no longer than a month.
In a pre-recorded speech to the Confederation of British Industry (CBI) conference, the Prime Minister said the new restrictions due to be voted on by MPs will "expire" on December 2 following speculation that the shutdown could be extended.
"I want to apologise to all of you who are experiencing the frustrations and the nightmare of the Covid world," he said.
"I know how tough it has been for you and I'm full of admiration for the determination you've shown in persevering through this crisis.
"I want to thank you for the heroic efforts you've made to look after your employees, to make your premises Covid-secure, putting in Perspex screens, all the trouble you've gone to in complying with the kinds of diktats that I never believed we would have to impose which, I assure you, go completely against every free market instinct I possess.
"And, believe me, we will end these autumn measures on December 2 when they expire."
But he said the lockdown, due to start on Thursday, is necessary if England is to push the rate of Covid-19 down and alleviate the strain on the NHS.
Cabinet Office minister Michael Gove had suggested on Sunday that the measures might have to be extended but the latest Government statements have rallied against the idea.
Foreign Secretary Dominic Raab, during an interview on Tuesday, said that next month's deadline for lifting the four-week lockdown is "written into law".
Asked on LBC radio whether people in England could mark the date of the end of the second national lockdown on their calendars, Mr Raab said: "Put it in your diary, it is written into law.
Mr Johnson had been due to address the CBI on Monday but was forced to postpone in order to take questions in the House of Commons about the month-long measures.
In his speech, filmed in Downing Street, he praised businesses that had stepped in to aid efforts against coronavirus this year by switching their production lines to make hand sanitiser gel, personal protective equipment and extra ventilators.
"It is thanks to British technical innovation that we are now in a far better position than we were during the first wave," said the Prime Minister, adding that there is the "prospect of a vaccine in the first quarter of next year", with UK scientists leading the charge.
He told the conference it would be businesses that help "drive our recovery" after the pandemic and pledged to "do whatever it takes" to help industry bounce back from the economic setbacks caused by coronavirus.
Taking the analogy of a business in Wales that has set up a trampolining centre in a disused coal mine, Mr Johnson said: "No matter how deep the hole you think you're in, you can always bounce back.
"And that is what we will do together."