Director of the Rosalind Franklin Institute, Professor James Naismith, told BBC Radio 4’s Today programme that people "shouldn't despair".
"If it spreads more quickly then, yes, it will get here - the travel ban will delay its arrival, but if it spreads more quickly the lesson has surely been from all the variants we’ve seen before that it will get here eventually," he said.
“We shouldn’t despair, vaccines will be effective, so if you haven’t had your vaccine go and get it, be that the booster, the first dose, the second dose.
“Secondly there are new medicines coming along… these will not be affected almost certainly by this mutation.
“We have got much better at controlling the disease in other ways in hospital so it is bad news but it is not doomsday.”
The new variant - called B.1.1529 - has 32 mutations located in its spike protein. Vaccines use spike proteins to provide immunity, and there are concerns that the mutations found mean the virus may make the vaccines less effective.
SAGE Professor Neil Ferguson, one of the architects of the UK's lockdown, described the new strain as "unprecedented".
“The B.1.1.529 variant has an unprecedented number of mutations in the spike protein gene, the protein which is the target of most vaccines," he said.
“There is therefore a concern that this variant may have a greater potential to escape prior immunity than previous variants.
“It is also concerning that this variant appears to be driving a rapid increase in case numbers in South Africa. The government's move to restrict travel with South Africa is therefore prudent."
Chief medical adviser to the UK Health Security Agency, Susan Hopkins, has warned that the new variant was the "most complex" and "most worrying" that we've seen.
On whether the variant had already arrived in the UK, Hopkins said "it's always possible".
"We have no cases identified whatsoever yet, nothing in our genome sequencing," she said.
"So overall, I think the situation is reassuring in-country, but of course, people are arriving every day.”
Government are also among those raising the alarm.
Health secretary Sajid Javid told MPs on Friday that the new variant was a reminder the pandemic is not over.
“Early indications show this variant may be more transmissible than the Delta variant, and current vaccines may be less effective against it," he said.
“It may also impact the effectiveness of one of our major treatments Ronapreve.”
He renewed his calls for people to come forward and get vaccinated.
"This variant is a reminder for all of us that this pandemic is far from over," he said.
"We must continue to act with caution and do all we can to keep this virus at bay, including once you’re eligible getting your booster shot."
Transport secretary Grant Shapps echoed the health secretary - rapidly placing most countries affected by the variant on the government's Covid travel red list.
Shapps tweeted late on Thursday evening: "UPDATE: from 12pm tomorrow 6 countries incl South Africa, Botswana, Zimbabwe, Lesotho, Eswatini & Namibia added to UK’s red list following early detection of the new B.1.1.529 variant abroad."
Adding: "Public safety is our priority. We’re taking this precautionary action to protect the progress we’ve made beating the virus across the country and as ever, we’ll continue to keep our measures under review"
On Friday morning, he told LBC that the new strain is "the most significant variant that has been encountered".
The transport secretary stressed that it was vital for the public to get vaccinated to avoid a repeat performance of the beginning of the pandemic, and that vaccines were the country's "main defence" against the virus.
"We don't want to go back to the bad old days," said Shapps.
A spokesman for the prime minister said the government is calling on people that have arrived from a country on the red list to get tested immediately.
"Anybody who has arrived from any of these countries in the last 10 days, NHS Test and Trace will be contacting them to ask them to take a PCR test," he said.
“But do not wait to be contacted. People shouldn’t wait to be contacted.
“If you have travelled back from one of the six countries in the past 10 days, they should take a PCR test.”
Read more: Is new COVID variant in UK? Does it cause more severe illness? What we know so far about B.1.1.529 strain found in southern Africa