www.gov.uk/guidance/national-lockdown-stay-at-home#staying-away-from-home-overnight
Staying away from home overnight
You cannot leave your home or the place where you are living for holidays or overnight stays unless you have a reasonable excuse for doing so. This means that holidays in the UK and abroad are not allowed.
This includes staying in a second home, caravan or boat, if that is not your primary residence. This also includes staying with anyone who you don’t live with unless they’re in your support bubble.
You are allowed to stay overnight away from your home if you:
are visiting your support bubble
are unable to return to your main residence
need accommodation while moving house
need accommodation to attend a funeral or related commemorative event
require accommodation for work purposes or to provide voluntary services
are a child requiring accommodation for school or care
are homeless, seeking asylum, a vulnerable person seeking refuge, or if escaping harm (including domestic abuse)
are an elite athlete or their support staff or parent provided the athlete is under 18 and it is necessary to be outside of the home in order to take part in training or a competition
Guest accommodation providers such as hotels, B&Bs and caravan parks may remain open for the specific reasons set out in law.
A full list of reasons can be found in the guidance on closing certain businesses and venues in England.
How the rules will change on 29 March
Some of the rules on what you can and cannot do will change on 29 March. You can read the ‘COVID-19 Response - Spring 2021’ for more information on the roadmap out of lockdown in England.
From 29 March:
you will be able to meet outdoors either in a group of 6 (from any number of households), or in a group of any size from up to 2 households (each household can include existing support bubbles, if eligible)
you will be able to take part in formally organised outdoor sports with any number of people (outdoor sports venues and facilities will be able to reopen)
childcare and supervised activities will be allowed outdoors for all children
formally organised parent and child groups will be able to take place outdoors for up to 15 attendees. Children under 5 will not be not counted in this number