Britain’s chief scientist Sir Mark Walport said the Ebola virus and other deadly foreign diseases are a “potential major threat” to Britain.
Sir Mark told the Daily Telegraph Ebola was a threat because of how “interconnected” the world is now.
Public Health England has issued a national alert to UK doctors amid fears the virus, which has killed some 670 people in West Africa, could spread.
It comes after an infected Liberian man travelled through a Nigerian airport.
UK Foreign Secretary Philip Hammond said Ebola was “a threat” and he would chair an emergency Cobra meeting about it later on Wednesday.
Several West African airlines have now stopped flying to Liberia and Sierra Leone over concerns about the outbreak.
Speaking to the paper, Sir Mark said: “The most dangerous infections of humans have always been those which have emerged from other species. They are a potential major threat to us.
“Emerging infectious disease is a global grand challenge. We were lucky with Sars. But we have to do the best horizon scanning.
“We have to think about risk and managing risk appropriately.”
Mr Hammond told the BBC he would hold a meeting of the government’s Cobra committee later to discuss the virus’ potential threat to the country.
“At the moment we don’t think any British nationals [abroad] are affected and we are fairly confident there are no cases in the UK.
“But it is a threat, it is something we need to respond to and we will be doing so through the Cobra mechanism.”
BBC global health correspondent Tulip Mazumdar said the West African outbreak has been ongoing for four months.
In that time local people have been looking after the sick and carrying out burials which actually can help spread the virus, she added, because it is spread by touching skin and bodily fluids