You can find full info here on the new Coronavirus rules for England (details for Scotland as they may be different as they set their own rules for Health matters). Summary of the changes is:

• From Friday 10 December, face coverings will be required by law in most indoor settings.
• From Monday 13 December office workers who can work from home should do so.
• From Wednesday 15 December, certain venues and events will be required by law to check that all visitors aged 18 years or over are fully vaccinated, have proof of a negative test in the last 48 hours, or have an exemption:

The use of the NHS COVID Pass is required as a condition of entry into the following places:

• Nightclubs, dancehalls and discotheques;
• Indoor events with 500 or more unseated attendees
• Outdoor events with 4,000 or more unseated attendees,
• Any events with 10,000 or more attendees indoor or outdoor