People living in the Tier 3 areas have been urged not to go on holiday this half-term.
Downing Street has encouraged all people who live in the areas under the highest level of lockdown restriction to sack off the half term getaway to help deal with the crisis.
Asked on Wednesday the Prime Minister's Official spokesman said that under the regulations people should not travel from at risk areas unless they met one of the excemptions.
It comes as thousands of families plan trips to unwind during the October half-term, which begins on Friday.
He said: "People should not travel outside the area except for a very short list of exemptions, such as for care or work purpose."
But Ministers have failed to make a foreign travel illegal under the guidelines.
This presents a problem for many travellers whose insurance could pay out if their trip was made impossible because of a change in government travel advice - but face being left out of pocket if it is just unenforceable guidance.
7.3million people in England are now in Tier 3 and living under the tightest restrictions.
As for those who were considering a trip in the UK, again travelling isn't illegal but gathering anywhere with people outside of your bubble is.
Similarly a request not to stay overnight in areas which are subject to Tier 3 guidance is not legally enforceable.
People living in the Tier 3/very high risk areas are subject to the more stringent rules, and are being asked to avoid travelling outside of their region to anywhere else in the UK - including other Tier 3 destinations.
Government guidance says: "People should try to avoid travelling outside the ‘Very High’ area they are in, or entering a ‘Very High’ area, other than for things like work, education, accessing youth services, to meet caring responsibilities or if they are in transit.
"People should avoid staying overnight in another part of the UK if they are resident in a ‘Very High’ area, or avoid staying overnight in a ‘Very High’ area if they are resident elsewhere."
