Enhanced screening for Ebola will begin at Britain's biggest airport today after the Health Secretary revealed the deadly virus is expected to reach the UK by January.
Jeremy Hunt said checks would begin at Heathrow's Terminal 1.
They will then be expanded to cover Gatwick airport and Eurostar rail terminals by the end of next week, after the death toll of the deadly virus in west Africa topped more than 4,000 people.
89% of passengers from badly-affected areas will be screened
Hunt told MPs it was "likely" that Ebola will be seen in the UK and a "handful" of cases could be confirmed in the next three months.
Screening and monitoring - including temperature checks and a questionnaire - at Heathrow, Gatwick and the Eurostar should ensure 89% of people travelling to the UK from the worst affected regions: Liberia, Sierra Leone and Guinea.
Checks will be carried out on people with tickets booked directly to the UK from those countries. There are no direct flights from the areas but there are indirect routes into the UK.
A Heathrow spokesman said "the welfare of our passengers and colleagues is always our main priority".
"We would like to reassure passengers that the Government assesses the risk of a traveller contracting Ebola to be low. We would encourage anybody with individual questions or concerns to refer to guidance from Public Health England and the Foreign Office," he added.
In a statement to the House of Commons yesterday, Hunt said: "This Government's first priority is the safety of the British people. Playing our part in halting the rise of the disease in west Africa is the single most important way of preventing Ebola affecting people in the UK.
"In the next week, Public Health England will start screening and monitoring UK bound air passengers identified by the Border Force coming on to the main routes from Liberia, Sierra Leone and Guinea.
"This will allow potential Ebola virus carriers arriving in the UK to be identified, tracked and given rapid access to expert health advice should they develop symptoms."
Enhanced checks start at Heathrow today
He said the measures will start at Heathrow Terminal 1, which receives around 85% of all such arrivals across the whole of the airport.
"They'll be expanded by the end of next week to other terminals at Heathrow and Gatwick and on the Eurostar which connects to Paris and Brussels bound arrivals from west Africa."
Mr Hunt said current advice suggested there will be fewer than 10 cases of Ebola in the UK over the next three months.
Anyone who tests positive for Ebola will be transferred to the Royal Free Hospital in north London, the UK's specialist centre for treating the most dangerous infectious diseases, Mr Hunt said.
There are also plans to increase bed capacity for Ebola patients in Newcastle, Liverpool and Sheffield, to make a total of 26 beds available, he added.
"I do believe we are amongst the best and most prepared countries in the world," he said.
"The situation will get worse before it gets better. But we shouldn't flinch in our resolve to defeat Ebola, both the safety of the British population and as part of our responsibility to some of the poorest countries on the planet."
Mr Hunt said the public health risk to the UK remained low but screening at airports could be extended to Birmingham and Manchester if the risk level increases.
He also announced that calls to the NHS's non-emergency 111 phoneline will be screened for potential Ebola sufferers.
David Cameron said Britain was doing more than almost any other country to help solve the crisis in west Africa after it was revealed the UK had committed £125 million to tackling Ebola.
The Prime Minister said: "Not only are we doing more than almost any other country in the world to deal with this problem at source in Sierra Leone and other countries, we are also taking very vigorous steps here to make sure we keep our people safe."
Britain's latest Ebola aid flight delivering beds, personal protection suits, tents and 10 vehicles landed in Freetown today, International Development Secretary Justine Greening said. It includes equipment for a 92-bed unit being built by a UK team.
Aid delivered so far includes ambulances, water tanks, incinerators for disposing of clothing and other materials, generators and personal protection equipment.
The World Health Organisation (WHO) has warned the epidemic is the "most severe acute health emergency in modern times", while the number of new cases of the disease is "rising exponentially" in the three hardest-hit countries - Guinea, Liberia, and Sierra Leone.
WHO director-general Margaret Chan said the Ebola outbreak had shown "the world is ill-prepared to respond to any severe, sustained, and threatening public health emergency".
The United States announced a Texas hospital worker who was in contact with Ebola victim Thomas Eric Duncan has become the first person to contract the infection within the country.
Officials in Dallas said there had been been a breach of protocol that led to the woman becoming infected after she wore full protective gear while treating Mr Duncan.