The universe could be a "vast and complex hologram" and our perception of life in 3D may only be an illusion, according to a theory put forward by astrophysicists.

The theoretical physicists, who have been investigating irregularities in the cosmic microwave background (the "afterglow" of the Big Bang), say they have found substantial evidence to support the idea of a holographic universe.

And the researchers from the University of Southampton, working with colleagues in Canada and Italy, say there is as much evidence for this theory as for traditional explanations for these irregularities.

A holographic universe, an idea first suggested in the 1990s, is one where all the information, which makes up our 3D "reality" (plus time) is contained in a 2D surface on its boundaries.

Professor Kostas Skenderis, of mathematical sciences at the University of Southampton, said: "Imagine that everything you see, feel and hear in three dimensions (and your perception of time) in fact emanates from a flat two-dimensional field.

"The idea is similar to that of ordinary holograms where a three-dimensional image is encoded in a two-dimensional surface, such as in the hologram on a credit card. However, this time, the entire universe is encoded."

He said the theory could be compared to watching a 3D film in a cinema. Although this is not a hologram, he explained that we see the pictures as having height, width and, crucially, depth when in fact it all originates from a flat 2D screen.

The difference, in our 3D universe, is that we can touch objects and the "projection" is "real" from our perspective, he said.

Prof Skenderis added: "Holography is a huge leap forward in the way we think about the structure and creation of the universe.

"Einstein's theory of general relativity explains almost everything large scale in the universe very well, but starts to unravel when examining its origins and mechanisms at quantum level.

"Scientists have been working for decades to combine Einstein's theory of gravity and quantum theory.

"Some believe the concept of a holographic universe has the potential to reconcile the two. I hope our research takes us another step towards this."

The researchers, from the University of Southampton (UK), University of Waterloo (Canada), Perimeter Institute (Canada), INFN, Lecce (Italy) and the University of Salento (Italy), have published their findings in the journal Physical Review Letters.