'Stolen' Charles Darwin Notebooks Mysteriously Returned

Two "stolen" notebooks written by Charles Darwin have been mysteriously returned to Cambridge University, 22 years after they were last seen.

The small leather-bound books are worth many millions of pounds and include the scientist's "tree of life" sketch.

But who returned the two postcard-sized notepads is a real whodunit. They were left anonymously in a bright pink gift bag containing the original blue box the notebooks were kept in and a plain brown envelope.

On it was printed a short message: "Librarian, Happy Easter X."

Inside were the two notebooks, wrapped tightly in cling film. The package had been left on the floor, in a public part of the library with no CCTV, outside Dr Gardner's office.

"I was shaking," says the university's librarian Dr Jessica Gardner of her reaction to seeing the bag and its contents for the first time on 9 March. "But I was also cautious because until we could unwrap them, you can't be 100% sure."

An agonising delay of five days followed between finding the package and the police granting permission to open the cling film, examine the notebooks and confirm they were genuine.

Their return comes 15 months after the BBC first highlighted they had gone missing and the library launched a worldwide appeal to find them.