Anyone spending time with family members from outside their own household at Christmas may be required to self-isolate for two weeks afterwards, newly released official documents suggest.

The advice to ?self-quarantine’ could be issued if festive gatherings of the wider family are allowed, ??????? a paper from the Scientific Advisory Group on Emergencies (Sage) warns.

The experts advising the Government caution that contact with multiple people raises the risk of getting and spreading Covid for up to a fortnight.

Prime Minister Boris Johnson (pictured on Friday in Leicester) has used the festive period as an incentive for people to follow the rules during England’s four-week lockdown

The paper says: ?After a period of high exposure to multiple contacts or ??????? different networks (eg a social gathering), the risk of spreading infection to other people can be reduced by avoiding contact as far as possible for two weeks (for example, by physical distancing within the home and self-quarantining to the extent that is feasible).’

Prime Minister Boris Johnson has used the festive period as an incentive for ???? people to follow the rules during England’s four-week lockdown.

At the Government press conference this week, he said: ?If we follow this package of measures in the way that we can and we have done before, I have no doubt people will be able to have as normal a Christmas as possible, and that we will be able to get things open before Christmas as well.’

But various experts have warned that if people can get together, more infections and deaths will follow.

The latest Sage advice to be released says any situation involving large numbers of contacts with different people increases the risk of Covid infection and transmission.

But the scientists warn that the risk is higher when people of different ages meet.

The document states: ?The risk of infection and transmission is raised for up to two weeks after contact with multiple people, places or social networks.’

Other advice released yesterday by the Scientific Pandemic Influenza Group on Behaviours (SPI-B) suggests young people could be given free mobile phone data and streaming services if they are asked to self-isolate.

Anyone spending time with family members from outside their own household at Christmas may be required to self-isolate for two weeks afterwards, newly released official documents suggest.

Pictured: A family have a Christmas dinner (stock image)

In another paper, positive strategies for helping people stick to the public health rules are discussed.

These include possible recommendations for people to greet each other by putting their hand over their heart instead of hugging, and holding ?doorstep celebrations’.

Ministers are believed to be considering cutting the current 14-day self-isolation period and ??????? a paper from last month on virus transmission suggests people are most infectious during their first week of symptoms, especially up to day five.