A rapid one-hour coronavirus test is now available at Heathrow Airport in a boost to the flagging travel industry.
Holidaymakers travelling to Hong Kong and Italy - which require pre-flight tests showing they don’t have it - can pay £80 for it before they fly.
It is the first time pre-departure Covid-19 testing has been made available at a UK airport, following repeated calls from travel bosses to introduce it.
The firms behind it, Collinson and Swissport, described it as the "crucial next step toward keeping the travel industry moving while limiting the spread of the virus".
Facilities at Terminals 2 and 5 at the airport will offer the private tests, which can be processed without being sent to a laboratory.
Passengers will need to book the saliva swab - known as a LAMP test - online before heading to the London airport.
The move aims to help passengers heading to countries where proof of a negative Covid-19 test is required on arrival.
Holidaymakers arriving in Italy from the UK have to show proof of a negative test before departure or take a test on arrival at an airport.
Hong Kong also requires travellers to show they have a negative test result, taken within 72 hours of a flight from London.
British Airways, Virgin Atlantic and Cathay Pacific will now offer the tests, which will initially be available for four weeks.
However, they are not currently available for anyone flying into the airport.
This means it will not have any effect on Britain’s 14-day quarantine rule for anyone arriving from "at-risk" destinations.
But it is hoped airport testing at UK airports will eventually replace the self-isolation period.
Heathrow boss John Holland-Kaye said: "These facilities will make it easier for passengers going to those countries to get a test and have the potential to provide a service for arriving passengers.
"Ultimately, we need a common international standard for pre-departure testing, and we welcome the UK Government's recent announcement that it wants to take a global lead in establishing this.
"We will work with them to make this happen as soon as possible so that we protect livelihoods as well as lives.”
Virgin Atlantic boss Shai Weiss said: "As long as the 14-day quarantine remains in place, demand for travel will not return and the UK's economic recovery, which relies on free-flowing trade and tourism, cannot take off.
"The Government's global travel task force must act swiftly to replace quarantine with passenger testing in November."
Ministers recently unveiled a task force to develop a testing system to potentially ease quarantine restrictions.
David Evans, joint chief executive officer at Collinson, said: "With countries around the world adding the UK to their list of high-risk countries, we need to find a way to work with governments, leading travel brands and other commercial entities to safely open up travel out of the UK."