British engineers have successfully tested a key component of an engine that could power a spaceplane from London to Sydney in under four hours.
The engineers have hailed it as the biggest breakthrough in aerospace propulsion "since the invention of the jet engine".
Oxfordshire-based Reaction Engines hope to build a rocket plane called Lapcat that would take off from an ordinary runway, reach speeds of around 19,000mph in the upper atmosphere and then land like a normal jet aircraft.
While still in the atmosphere, the plane's Sabre engine would combine on-board hydrogen fuel with oxygen that it "breathes" from the air. But the air needs to be super-cooled for the engine to work.
The company has now demonstrated a lightweight heat exchanger that pre-cools incoming air from 1000 degrees Celsius to minus 150 degrees in 1/100th of a second - six times faster than the blink of an eye - without blocking pipes with a layer of frost.
Alan Bond, who founded the company and led the research, said: "The team has been trying to solve this problem for over 30 years and we've finally done it.
"The Sabre engine has the potential to revolutionise our lives in the 21st century in the way the jet engine did in the 20th Century."
The tests were validated by the European Space Agency .
Science Minister David Willetts MP said: "This is a remarkable achievement for a remarkable company. Building on years of unique engineering know-how, Reaction Engines has shown the world that Britain remains at the forefront of technological innovation and can get ahead in the global race."
The Sabre engine could also power a re-useable rocket plane called Skylon that could carry a large payload into space, reducing the cost of launching a satellite by more than 10 times.
By using available oxygen in the atmosphere it would reduce the amount of fuel it needs to carry, so it could reach orbit in a single stage. Current rockets require costly multiple stages which are jettisoned during their ascent.