The Prime Minister announced new measures to combat more dangerous strains of the virus coming into Britain, as well the number of people coming from high risk countries.
But First Minister Nicola Sturgeon has called for a “comprehensive system of supervised quarantine” for travellers arriving in the UK, as she said Mr Johnson’s current plan does not go far enough.
Making a statement in the Commons, Mr Johnson said: “I want to make clear that under the stay at home regulations, it is illegal to leave home to travel abroad for leisure purposes and we will enforce this at ports and airports by asking people why they are leaving and instructing them to return home if they do not have a valid reason to travel.
“We have also banned all travel from 22 countries where there is a risk of known variants, including South Africa, Portugal and South American nations.
“And in order to reduce the risk posed by UK nationals and residents returning home from these countries, I can announce that we will require all such arrivals who cannot be refused entry to isolate in government-provided accommodation, such as hotels, for ten days without exception.
“They will be met at the airport and transported directly into quarantine. The Department of Health and Social Care is working to establish these facilities as quickly as possible.”
Passengers returning from the “red-list countries” will face strict isolation rules, with passengers forced to pay around £1,500 for a ten-day stay in a hotel.
Under the new rules, travellers will be met at the airport and transported directly into quarantine, while those hoping to travel will have to apply to do so first.
However, following a call with members of the UK, Welsh, and Northern Irish governments about the plan, Ms Sturgeon criticised the “minimal” proposals.
She said they left “far too many weak points and gaps” for Covid-19 and any variants of the virus to enter the country.
“I think I do have a duty at this point to say that I am concerned that the proposal does not go far enough and I’ve made that point very strongly in the four-nations discussions that we’ve just had today,” she said.
“So while the Scottish Government will initially emulate the UK Government’s steps on enhancing quarantine arrangements, we will be seeking urgently to persuade them to go much further and indeed to move to a comprehensive system of supervised quarantine.
“Given the obvious practical issues involved, we are very clear that our preference is to have consistent quarantine rules across the UK, but if there is no agreement to go further on a four-nations basis, we will be considering going further ourselves and we will set out any such additional measures next week.
“If you impose [quarantine measures] purely for the countries where there is a travel ban in place, the very fact that there is already a travel ban in place tells you you’re going to be reaching very, very small numbers of people because nobody should be travelling from these countries even for essential purposes already.
“And if you focus just on countries with a variant has been identified – South Africa, or countries where it is known to have been identified – then you possibly miss countries where it has already travelled to but hasn’t yet been identified.
“When you’re trying to stop a virus getting into the country and, in particular, stop new variants getting into the country, you really have to have as comprehensive a protective ring as possible because the virus will find the holes in the net and it will get through the holes in the net.”
Ms Sturgeon added: “We will try to encourage a four-nations approach that goes much further – much further.
“If we can’t reach that or we can’t reach that quickly enough, we will consider what it is practical for us to do it ourselves and we will set that out in the coming days.”
Earlier Home Secretary Priti Patel warned anyone found at the border without a good reason will be sent home or fined.
She said: “It is clear that there are still too many people coming in and out of our country each day.
“And today I am announcing further action to strengthen the health measures we already have at the border, but to reduce passenger flow so that only a small number of people for whom it is absolutely essential to travel are doing so and therefore reducing the risk to our world-leading vaccine programme.”
Ms Patel also warned “going on holiday is not a valid reason” to ignore the stay-at-home rules.
She told the Commons: “For those travelling out of the UK, we will also be enhancing and stepping up enforcement rules.
“Because despite the stay-at-home regulations, we are still seeing people not complying with these rules.
"The rules are clear – people should be staying at home unless they have a valid reason to leave.”
Shadow home secretary Nick Thomas-Symonds accused the UK Government of “lurching from one crisis to another”.
He said: “We must learn from past mistakes and crucially act now, and one of the key areas where the Government has fallen short is on protecting our borders.
“And I’m deeply concerned that the measures outlined today are yet another example of this – too little, too late.
"Yet again, the Government is lurching from one crisis to another devoid of strategy.”