The man, 68, must continue to serve his 12-year sentence even though the girl, known as M, said she lied at trial, The Times reports.

Three appeal judges heard she invented the allegations in order to gain the attention of family, her teachers and her classmates.

However, the court has ruled the original trial in January last year at Snaresbrook Crown Court remained believable.

In a ruling handed down on Friday, they said the girl seemed to be motivated by regret that her grandfather had been jailed.

The girl’s mother gave evidence at the trial of the grandfather, her father-in-law. She denied she had told her daughter to make the allegations because of her own dislike for the man. Evidence was also given by the girl’s counsellor and a police officer who had interviewed her.

The grandfather was convicted by a majority verdict of 11 to 1 in February last year.

But, three months later, an appeal was lodged on the sole ground that M had given false evidence at trial.

She retracted her allegations in a 16-paragraph statement witnessed by a solicitor.

It stated she was “shocked and horrified to discover that my grandfather was not only convicted but had gone to prison. This was never my intention and was not what was supposed to happen. I was just supposed to get attention and that would be it.”

Her mother supported the retraction.

The Court of Appeal, led by Lord Justice Davis, however, rejected the appeal.

The judges ruled that M’s “re-traction is … demonstrably unreliable”.