People are now being advised to take a Covid test before going to places such as Christmas markets and busy city centres, as well as before Christmas parties and family gatherings.
It is the first time the Government has advised people to take a lateral flow test before going to potentially busy or dangerous locations.
Previous advice was to get yourself tested if you have potentially been exposed - so after an event - as well as regular testing.
The new guidance would help stop the spread of coronavirus by preventing people going to busy locations if they test positive.
It comes as a new Delta plus variant spreads through the UK, which is said to be more infectious and more likely to spread without symptoms.
12% of tested cases have been found to be the new variant.
The guidance doesn't mention specific events or locations, but now states: "You may wish to take a rapid lateral flow test if it is expected that there will be a period of high risk that day.
"This includes spending time in crowded and enclosed spaces, or before visiting people who are at higher risk of severe illness if they get Covid-19."
Crowded and enclosed spaces would include Christmas markets, shops, shopping centres, city centres and Christmas parties.
People at higher risk could include older and vulnerable members of your family at small gatherings and meals over the festive season.
A Government spokesperson told inews : “About 1 in 3 people with Covid-19 do not have any symptoms but can still infect others. Rapid testing plays a critical role in uncovering hidden cases of Covid-19 and preventing the spread of the virus.
“Taking a free rapid lateral flow test before a period of high risk will give you peace of mind that you are unlikely to be infectious and able to spread Covid-19.
“It remains vital to get vaccinated and continue to take other preventative measures such as regular handwashing, wearing a face mask and keeping spaces ventilated when meeting people indoors.”
