Visitors will get an unprecedented, closer look at eight mummies in a new exhibition opening at the British Museum.

The mummies, which cover a period of more than 4,000 years and include two children, a temple singer and a doorkeeper, have been subject to scientific investigation using a new generation of medical CT scanners.

Through the use of technology, visitors will be able to see inside the mummy cases and examine the bodies and ornaments placed on some of them while their layers of wrapping are left intact.

The eight individuals include a 1.7m mummy from the Roman period which was discovered in the 1820s but puzzled experts because it appeared to have prominent breasts as well as a painted beard.

Using CT technology, researchers have now confirmed that he is a man after all and that his breasts and thighs were plumped out, by his embalmers, with cloth padding inserted underneath his wrappings.

Curator Dr John Taylor said: "It was very puzzling. He has a beard painted on his wrapping but his breasts looked plumped up. There's always been this question: 'Is this a man or a woman?' Now we've done the scans we know this is a man."

He added: "His family must have wanted him to look like that in death. But his skin is quite loose over his bones suggesting that his appearance relates to how he looked in life.

"But showing him overweight was very unusual. Normally they presented mummies as young and physically idealised. "

The mummy of a child temple singer, embalmed at around seven or eight years of age, is also on display, with digital visualisations revealing developing teeth and long hair.

Visitors will be able to see the amulets and "magical trappings" placed on a female adult temple singer, who was subject to an elite burial, the highest level of mummification available at around 900BC.

She is thought to have suffered from cardiovascular disease, as it was discovered that the arteries in her legs were covered in calcified plaque.

Another mummy, from a medieval Christian community, was found to have a tattoo on her inner thigh, representing a monogram of the Archangel Michael, patron saint of the Sudan.

A brain-removal tool used by ancient Egyptian embalmers was discovered lodged in the skull of a female mummy which dates back aro 2,400 years.

The mummies date from the Predynastic to the Christian era and from sites in Egypt to Sudan, while the youngest individual on display is thought to be around two or three years old.

Dr Taylor said that the researchers had made surprising discoveries about the health of ancient Egyptians.

He said: "We found fatty deposits in their arteries which was very surprising. It's the kind of thing you'd normally associate with modern day living and high cholesterol."

He added: "We are seeing things that we couldn't have seen five years ago. Over the next five years they'll be more advances and we'd hope to have even greater clarity.

"We've only looked at eight of the 120 mummies in the collection. There is potential there for looking at more."

Neil MacGregor, director of the British Museum which obtained its first mummy in 1756, said: "This new technology is truly ground-breaking, allowing us to reconstruct and understand the lives of these eight, very different, individuals.

"This is a project which has only been made possible through recent technological advances and I am delighted that the museum is at the forefront of this kind of research and presentation."

:: Ancient Lives, New Discoveries is sponsored by Julius Baer and runs from May 22 to November 30 at the British Museum.