José Manuel Soria has denied all alleged links to the company, set up by the Panamanian law firm at the centre of the scandal Mossack Fonseca, after he and his brothers were named as administrators.
Soria still denies any wrongdoing and said he was instead stepping down to minimise the damage posed to the placeholder government, run by the People’s Party, which has been in power since national elections proved inconclusive last December.
His links to the companies were first unearthed by two Spanish newspapers on Monday, naming Soria as a director of UK Lines, a company registered in the Bahamas in the 1990s.
Soria originally said he had never “had shares, nor participation, nor any position of responsibility” in the company, the Associated Press reported on Monday, but that a British company with the same name provided services for a family business he used to run.
It was then reported that he had been president of another offshore company, formerly known as UK Lines, and had links to another company in Jersey.
Soria continued to deny having any links to the companies. A company document from 2002 was then discovered bearing his signature, prompting him to stand down.
Soria still denies the allegations, but admits he handled the situation badly.
His resignation letter reads: “In light of the errors committed in recent days in the explanations I gave regarding my business activities... and the lack of precise information about things that occurred more than 20 years ago, I have informed the prime minister of my irrevocable decision to resign.
“Politics is an activity that must at all times be exemplary both in its pedagogy and its explanations. When that does not happen, the corresponding responsibilities must be accepted.”