SAGE advised that all UK-bound arrivals be placed in quarantine for five consecutive days, and subject to a predeparture PCR test.
According to the expert panel, the existing travel bans are allowing infected individuals to slip through.
Currently, anyone who has been fully vaccinated and intends to enter the UK must take a PCR test within two days after returning.
They can do this immediately upon landing and get a result the next day. This will release them from their isolation within hours.
SAGE scientists stated that this may not allow enough time for virus incubation. Ministers should also bring day 5 and 8 tests.
Before flying back to Britain, unvaccinated passengers entering the UK will need to pass “fit to fly” tests.
SAGE’s updated advice was revealed from the minutes of an urgent meeting regarding Omicron variant Monday.
The video conference, which was hosted by Professor Chris Whitty and Sir Patrick Vallance as chief scientific advisers, attracted more than 30 scientists.
The experts also suggested that Britain must be prepared for an ‘potentially extremely significant wave with associated hospitalsisations’ in the winter, if Omicron is true.
Boris Johnson tightened travel guidelines yesterday so that arrivals must self-isolate till they obtain a negative PCR result.
Shadow home secretary Yvette Cooper said today that it was ‘totally inacceptable’ for ministers to ignore advice from scientists and impose further curbs at border.
It was rejected this week by the Government, which argued it would have a detrimental impact on travel and tourism.

The UK has seen 22 Omicron varaint cases. One event is responsible for all nine cases in Scotland. Each of the 13 England locations is linked to travel abroad

Scientists at SAGE have asked for the immediate acceleration of testing for vaccine-infected arrivals. (Pictured, BA flight departs Heathrow.
The airport offers a Covid test to help vaccinated arrivals avoid isolation. They can get their results within three hours.
Some testing companies, including ExpressTest, offer this package for £119.
There have been 22 confirmed Omicron cases, but many more are under investigation.
The links between the cases in Scotland were confirmed by Nicola Sturgeon yesterday.
However, there are concerns that the virus could already be spreading in this country.
In the minutes, seen by the BBC but yet to be published, SAGE scientists say extra swabs for travellers returning to the UK would be ‘valuable’.
It was also mentioned that there are still uncertainties about the variant’s effectiveness and transmissibility against vaccines.
Ms. Cooper lashed out at ministers who failed to listen to scientists’ advice.
She declared: “It’s totally unacceptable ministers fail to take action at border, when their own advisors are telling them they should introduce pre-departure checks.
“It’s absurd to believe that anyone can fly from one country to another, get on a flight and wait in line at the departure gate, then board and ride on buses and trains throughout the UK. All this without ever having passed a screening test.
“The Government should not make the same mistake it did in pandemic response by taking too long to address the Omicron variant’s entry into the UK.
Boris Johnson introduced stricter restrictions to arrivals, citing concern about the Omicron variant. He also stated that these would hinder the UK’s’seeding’.
Nicola Sturgeon & Mark Drakeford, however, have requested that the Prime Minister go even further to place all new arrivals in quarantine for 8 days.
According to official statistics, around 500,000 people arrived in the UK daily before the pandemic. But, it is believed that this number was much lower.
Between the detection of the Omicron variant and the imposition of travel restrictions, up to 50 direct flights from South Africa arrived at the UK.
Now anyone coming from the red list country has to go into mandatory hotel quarantine for 11-days at a cost of £2,285.
Six countries from southern Africa were also affected by the restriction.
Unvaccinated Arrivals were required to undergo a Covid Test three days prior to departure and again on the second and eighth day after arrival. For ten days, they must be self-isolated.
They must take the Covid test and self-isolate within two days after arriving. If the test results are negative, they can leave self-isolation.
Johnson said Omicron cases must be isolated and that he has brought back face masks in stores, public transport and school hallways.
He has been under increasing pressure to tighten restrictions amid concerns about the Omicron version’s spread.
The head of UK Health Security Agency Dr Jenny Harries said that socializing in the lead up to Christmas should be avoided.
Some experts even advocate that teachers should use face masks in class again.
The virus has been stopped from spreading to Scotland by encouraging people to return to their homes.
Although scientists are working tirelessly to identify the danger, they don’t expect any concrete findings for at least the next two weeks.
The UK Health Security Agency’s top epidemiologists say that they will need to identify hundreds of cases before making any concrete claims about its transmissibility.
Israeli news website Channel 24 claimed yesterday Omicron could be up to 1.3 times as infectious as Delta. But they failed to provide data. Israeli Health Ministry denied that the claim was true.