A further 20 million people in England will join the toughest tier of Covid restrictions from Thursday.
The Midlands, North East, parts of the North West and parts of the South West are among those escalated to tier four.
And secondary schools across most of England are to remain closed for an extra two weeks for most pupils.
The public must “redouble” its efforts at this “critical moment”, the PM said, before adding he was confident things will be “very much better” by 5 April.
“All of these measures in the end are designed to save lives and protect the NHS,” he said at a Downing Street briefing. “For that very reason, I must ask you to follow the rules where you live tomorrow night and see in the new year safely at home.”
Earlier, the Oxford-AstraZeneca vaccine was approved for use in the UK, with the first doses to be given on Monday.
But Boris Johnson warned that people should not “in any way think that this is over” as “the virus is really surging”.
His comments came as a further 50,023 new Covid cases were recorded in the UK on Wednesday, as well as 981 more deaths within 28 days of a positive test – more than double Tuesday’s total.
Under tier four rules, non-essential shops, beauty salons and hairdressers must close, and people are limited to meeting in a public outdoor place with their household, or one other person.
Health Secretary Matt Hancock told MPs that rising cases across England mean it is “therefore necessary to apply tier three measures more broadly too, including in Liverpool and North Yorkshire”.
In tier three areas, household mixing is banned indoors and in private gardens, while the rule of six applies in public spaces. Shops, gyms and personal care services can remain open, but hospitality settings must close except for takeaway.
All of the tier changes will come into effect at 00:01 GMT on Thursday 31 December.
The areas joining tier four from Thursday are:
- Leicester City
- Leicestershire (Oadby and Wigston, Harborough, Hinckley and Bosworth, Blaby, Charnwood, North West Leicestershire, Melton)
- Lincolnshire (City of Lincoln, Boston, South Kesteven, West Lindsey, North Kesteven, South Holland, East Lindsey)
- Northamptonshire (Corby, Daventry, East Northamptonshire, Kettering, Northampton, South Northamptonshire, Wellingborough)
- Derby and Derbyshire (Derby, Amber Valley, South Derbyshire, Bolsover, North East Derbyshire, Chesterfield, Erewash, Derbyshire Dales, High Peak)
- Nottingham and Nottinghamshire (Gedling, Ashfield, Mansfield, Rushcliffe, Bassetlaw, Newark and Sherwood, Nottinghamshire, Broxtowe)
- Birmingham and Black Country (Dudley, Birmingham, Sandwell, Walsall, Wolverhampton)
- Warwickshire (Rugby, Nuneaton and Bedworth, Warwick, North Warwickshire, Stratford-upon-Avon)
- Staffordshire and Stoke-on-Trent (East Staffordshire, Stafford, South Staffordshire, Cannock Chase, Lichfield, Staffordshire Moorlands, Newcastle under Lyme, Tamworth, Stoke-on-Trent)
- Lancashire (Burnley, Pendle, Blackburn with Darwen, Ribble Valley, Blackpool, Preston, Hyndburn, Chorley, Fylde, Lancaster, Rossendale, South Ribble, West Lancashire, Wyre)
- Cheshire and Warrington (Cheshire East, Cheshire West and Chester, Warrington)
- Cumbria (Eden, Carlisle, South Lakeland, Barrow-in-Furness, Copeland, Allerdale)
- Greater Manchester (Bolton, Bury, Manchester, Oldham, Rochdale, Salford, Stockport, Tameside, Trafford, Wigan)
- Tees Valley (Darlington, Hartlepool, Middlesbrough, Redcar and Cleveland, Stockton-on-Tees )
- North East (County Durham, Gateshead, Newcastle-upon-Tyne, North Tyneside, Northumberland, South Tyneside, Sunderland)
- Gloucestershire (Gloucester, Forest of Dean, Cotswolds, Tewkesbury, Stroud, Cheltenham)
- Somerset Council (Mendip, Sedgemoor, Somerset West and Taunton, South Somerset)
- Bournemouth, Christchurch and Poole
- Isle of Wight
- New Forest
The areas joining tier three are:
- Shropshire and Telford & Wrekin
- Worcestershire (Bromsgrove, Malvern Hills, Redditch, Worcester, Wychavon, Wyre Forest)
- Liverpool City Region (Halton, Knowsley, Liverpool, Sefton, Wirral, St Helens)
- York & North Yorkshire (Scarborough, Hambleton, Richmondshire, Selby, Craven, Ryedale, Harrogate, City of York)
- Bath and North East Somerset
- Devon, Plymouth, Torbay (East Devon, Exeter, Mid Devon, North Devon, South Hams, Teignbridge, Torridge, West Devon, Plymouth, Torbay)