Lockdown restrictions in England from 5th January

Tier 1: Medium Tier 2: High Tier 3: Very High Tier 4: Stay at Home National Lockdown
National lockdown All areas of England are currently in full lockdown until at least 22nd February. You should not leave home unless you have a "reasonable excuse," with fines of up to £6,400 for non-compliance.

Lockdown is equivalent to Tier 4, with additional restrictions. New restrictions in place during this time are highlighted in black below.
Face coverings Everyone must wear a face covering in indoor public settings, unless they have an exemption.
Support bubbles and extended households You may form an exclusive support bubble with a single person (for example, one multi-person household may join with a single one-person household, or two single-person households may form a bubble together).
Socialising Up to six people from any number of households, indoors or outdoors. Up to six people from any number of households, outdoors only. Up to six people from any number of households, in public areas (such as parks) only. Up to two people from up to two households, in public areas (such as parks) only. You may only socialise with people within your household or social bubble. You are not allowed to meet others for the purpose of leisure or recreation. You may meet one person from outside of your household for the purposes of exercise.
Working Everyone who is able to work from home should do so. Key workers should continue travelling to the workplace. Public-sector employees should go to the workplace where necessary. The clinically vulerable should not leave home to go to work, regardless of profession.
Public transport Walk or cycle if possible. Plan ahead to avoid busy times and routes.
Travel into Tier area Allowed. Discouraged. You may pass through a Tier 2 area as part of a longer journey. Discouraged. Avoid travelling from a lower tier area into a Tier 3 area. You may pass through a Tier 3 area as part of a longer journey. Extremely discouraged. People from lower tiers should not enter a Tier 4 area without a valid reason. You may pass through a Tier 4 area as part of a longer journey.
Travel out of Tier area Allowed. Discouraged. If travelling to a Tier 1 area, continue to follow Tier 2 rules. Discouraged. Avoid travelling out of the Tier 3 area. If you do, continue to follow Tier 3 rules. Extremely discouraged. Do not leave home without a valid reason. You must not leave the Tier 4 area without a valid reason. Tier 4 residents are forbidden from travelling abroad.
Overnight stays in Tier area Allowed. Forbidden.
Retail (essential and non-essential) Open; including indoor and outdoor markets. Essential retail, such as food stores and pharmacies, only.
Food and drink venues selling for consumption on premises (restaurants, pubs and bars) Open. Must provide table service only, must stop taking orders at 10pm and be closed between 11pm and 5am. Restaurants open. Pubs and bars must close, unless serving substantial meals, and may only serve alcohol with food. All must provide table service only, must stop taking orders at 10pm and be closed between 11pm and 5am. Closed; except for takeaway. All venues must stop selling food for takeaway after 11pm. Venues are no longer allowed to sell alcohol for takeaway, but may continue doing so for home delivery.
Food and drink venues selling for consumption off premises (restaurants with delivery, click-and-collect, or drive-thru facilities) Open without time restrictions.
Personal care (hairdressers, barbers, beauty salons, tattoo parlours, tanning salons, and spas) Open. Closed.
Outdoor public entertainment venues (theme parks, funfairs, zoos, botanical gardens, heritage sites) Open; but must close by 11pm. Open; except for indoor areas. Indoor gift shops, toilets and thoroughfares may remain open. Closed; except for the grounds of gardens and heritage sites.
Indoor public entertainment venues (cinemas, theatres, museums, casinos, bowling alleys, bingo halls) Open; but must close by 11pm. Cinemas and theatres may remain open past 11pm for shows that started before 10pm. Closed.
Nightclubs, discos, gentlemen's clubs Closed.
Performances and shows (at cinemas, theatres, concert halls) Allowed. Venues may remain open past 11pm for shows that started before 10pm. Attendance is limited to whichever is lower: 50% capacity, 4000 people for outdoor events, or 1000 people for indoor events. Allowed. Venues may remain open past 11pm for shows that started before 10pm. Attendance is limited to whichever is lower: 50% capacity, 2000 people for outdoor events, or 1000 people for indoor events. Forbidden.
Accommodation services (hotels, hostels, campsites, B&Bs) Open. Closed, except for essential use.
Sport and leisure facilities (gyms, sports courts, leisure centres, swimming pools, golf courses and playgrounds) Open. Open; however classes and group activities taking place indoors are forbidden. Saunas and steam rooms must close. Indoor facilities must close. Outdoor facilities are permitted to open. All sporting facilities must close, both indoor and outdoor.
Outdoor sports (organised sports, activities and exercise classes) Allowed. Allowed; however high-contact sports should be avoided. Allowed for under-18s and disabled people only. Allowed for disabled people only.
Indoor sports (organised sports, activities and exercise classes) Allowed; limited to groups of six. Allowed; however only if it is possible to not mix with other households or social bubbles. Forbidden.
Spectator sports Allowed; attendance is limited to whichever is lower: 50% capacity, 4000 people for outdoor events, or 1000 people for indoor events. Allowed; attendance is limited to whichever is lower: 50% capacity, 2000 people for outdoor events, or 1000 people for indoor events. Closed to spectators.
Schools, colleges and universities Open. Students should attend as normal, unless they are self-isolating. Open. Students should attend as normal, unless they are self-isolating. Extra-curricular activities are forbidden. Closed; schools, colleges and universities are remote-learning only. Summer examinations for GCSEs and A-levels have been cancelled, however are still going ahead for BTec students. Examinations taking place in January are continuing as planned. University students should stay where they are and not travel back to their university residence. In-person teaching is continuing for medical, veterinary, and teacher training courses only.
Libraries and community centres Open, but cannot host private hire events. Open, but cannot host any social activities. Community centres must close. Libraries remain open for click-and-collect and digital services only.
Places of worship Communal worship allowed, but can only socialise in groups of up to six people. Individual worship allowed, but you are forbidden from socialising with anyone outside of your household or social bubble.
Weddings Allowed; limit of 15 people for both weddings and wedding receptions. Allowed; limit of 15 people for weddings. Wedding receptions are forbidden. Forbidden; unless in exceptional circumstances. In exceptional circumstances, limited to 6 people.
Funerals Allowed; limit of 30 people for funerals and 15 people for commemorative events (e.g. wakes). Allowed; limit of 30 people for funerals and 6 people for commemorative events (e.g. wakes).
Care homes Visits allowed where arrangements such as screens, visiting pods or window visits are available. Close-contact visits supported by testing are allowed. Visits allowed where arrangements such as screens, visiting pods or window visits are available. Close-contact visits are not allowed under any circumstances. Visits allowed where arrangements such as screens, visiting pods or window visits are available. Close-contact visits are not allowed under any circumstances. All visits will be cancelled in the event of an outbreak at the care home.
Other services The following may remain open: agricultural supply shops, animal boarding facilities, animal rescue facilities, banks and building societies, bicycle shops, building merchants and building product suppliers, car parks, car washes (automatic only), christmas tree retailers, civil registrations offices, courts and probation services, funeral directors, Jobcentre Plus offices, laundrettes and dry cleaners, medical centres and dental services, mobility and disability support shops, money transfer businesses, motorway service areas, off-licenses, passport and visa services, pet groomers (for welfare services only), pet shops, petrol stations, post offices, public toilets, repair services, short-term loan providers, storage and distribution facilities, taxi and vehicle hire, vehicle repair and MOT services, veterinarians, victim services, waste and recycling centres.

Disclaimer: This information is based on the published advice by each devolved government at the time that I look at it. It's not complete; it's not meant to be. There's a whole lot of exceptions and other random information that is impractical to display as a table—which is probably why they don't do it. Check your respective nation's official guidance if you think something seems off.