Scientists claim to have spotted echoes of the Big Bang for the first time, a discovery some consider to be the “Holy Grail” of astronomy.

The extraordinary find, which is already being hailed as worthy of a Nobel Prize, could reveal how the universe was born 14 billion years ago.

Astrophysicists at the Harvard-Smithsonian Centre for Astrophysics announced they have detected primordial gravitational waves, tiny ripples in the fabric of the universe left over from those first moments.

John Kovac, associate professor of astronomy at the Centre, who led the research, said: “Detecting this signal is one of the most important goals in cosmology today.”

The existence of the waves backs up the theory of cosmic inflation, that in the first trillionth of a trillionth of a trillionth of a second the universe expanded faster than the speed of light.

The signal, detected by a specialised telescope at the South Pole called BICEP2, was far stronger than predicted.

Dr Clem Pryke of the University of Minnesota, who was also on the research team, said: “This has been like looking for a needle in a haystack, but instead we found a crowbar.”

Gravitational waves were predicted by Albert Einstein’s general theory of relativity, but they have never been observed before.

The results will have to be confirmed by other research teams.

Astrophysicist Professor Avi Loeb, from Harvard University, said: “This work offers new insights into some of our most basic questions.

“Why do we exist? How did the universe begin?

“These results are not only a smoking gun for inflation, they also tell us when inflation took place and how powerful the process was.”

Physicist and science presenter Martin Archer told Sky News: “The signs of both inflation and gravitational waves in the same experiment is quite frankly amazing.”