The BBC's Lindsey Thorne: Women MPs are wearing jeans to work in protest

Five MPs displayed signs reading "Jeans: Alibi for rape" on the steps of the parliament building in Rome.

The protest came after the Supreme Court of Appeal in Rome overturned a rape conviction on Wednesday, saying the supposed victim must have agreed to sex because her jeans could not have been removed without her consent.

David Willey: Case highlights Italy's inadequate rape laws

Alessandra Mussolini, the granddaughter of dictator Benito Mussolini and a right-wing MP, said the ruling "offends the dignity of women."

She vowed to continue the protest until the Constitutional Court overruled the decision.

Horrified reaction

The ruling drew horrified reaction from across the political spectrum.

Centre-left deputies initiated an emergency debate in Parliament on Thursday afternoon.

"It's absurd. The Court of Appeal should be reminded of the existence of zippers," said Justice Ministry Undersecretary Maretta Scoca.

A female Supreme Court judge, Simonetta Sotgiu, hit out at her colleagues.

"The appeals court is in the hands of men, often elderly, with old-fashioned ideas. Every day I have to do battle to change the mentality," she said.

The head of an anti-crime telephone hotline said the service had been overwhelmed with calls from women worried about the implications of the "mediaeval" ruling.

"This decision is going to make it even harder for victims to take the step of pressing charges," said Giuliana dal Pozzo, president of the Telefono Rosa (Red Telephone) helpline.

Conviction quashed

The appeal to the Supreme Court - Italy's supreme judicial body - was brought by a driving instructor, Carmine Cristiano.

He had been sentenced to 34 months' in jail for raping an 18-year-old pupil by a lower court in the southern town of Potenza.

His defence had argued that the young woman - identified as Rosa - had consented to sex, a version of events which she strongly denied.