A former senior manager of Charing Cross Hospital has fervently denied allegations that she used NHS funds to import horse sperm for her stud farm.
Louise Tomkins, who left her job in June, was recently arrested by the Metropolitan police who were investigating allegations of fraud at Imperial College Healthcare NHS Trust, which runs the hospital in Fulham Palace Road.
Mrs Tomkins, who is the daughter of a former British ambassador to France said the claims were "rubbish".
She said: "There is an ongoing investigation into some invoices that I issued, but it's got nothing at all to do with horse semen and IVF treatment. That's all rubbish."
Mrs Tomkins said she was co-operating with the police investigations, but denied all the accusations.
Internal audits revealed unusually large purchases of human semen from overseas suppliers.
Invoices worth several hundred thousand pounds had allegedly been created to account for the transactions, but later checks revealed the companies had supplied thoroughbred horse sperm.
Mrs Tomkins, who is the daughter of the late Sir Edward Tomkins, a former British ambassador to Paris and The Hague, said she left her post as a senior general manager at the hospital in June after an employment restructure.
She now runs Southfield Stud in Horsham, West Sussex full time.
Its website describes it as "a small breeding operation which aims to breed good competition horses by using top-class proven mares from known pedigrees and crossing them to stallions known to improve performance and temperament".
A spokeswoman for the trust declined to comment on the matter, but police confirmed a 45-year-old woman had been arrested and bailed over allegations of fraud at the trust.
Hammersmith Hospital is a leading provider of IVF treatment, but it stressed it does not use horse semen in treatments.