The woman, who was under house arrest and wearing an ankle tag, was employed by an external cleaning company and was responsible for tidying the Prosecutor's Office and court building.

All cleaners employed at the court are given a master key and have access to the offices of all judges and prosecutors.

The cleaning staff are supposed to be carefully selected as on occasion they may tidy away files containing sensitive data.

Court judges had no idea that the woman was a convicted criminal, and her ankle tag was not visible under her clothing.

Whilst working at the courthouse the woman stole small amounts of money from a communal office coffee fund, as well as an expensive perfume belonging to an office manager. It was only when she was caught stealing food from a communal fridge that it emerged she was a convicted criminal.

She has now been sentenced to four months in prison. Her previous criminal record had a limited duty of disclosure and therefore had not been revealed to her employer.

Vienna’s High Court (OLG) is responsible for awarding contracts to cleaning companies, but court spokesman Reinhard Hinger stressed that it had to “trust that these companies do not employ people who steal or peek into files.”

He admitted that the fact that court cleaning had been outsourced to external companies for cost cutting purposes did present “a security risk”.

Last week it emerged that staff at Vienna’s Regional Court had thrown confidential documents relating to ongoing cases in a paper recycling bin on the street.

Documents relating to a recent case involving fake, prescription-only medicines, which involved police in Austria, Belgium, Cyprus, Hungary and Britain were also found – and could potentially have alerted the dealers of their imminent arrests if they had fallen into the wrong hands.