An Italian sailing champion turned MP – who justified frequent parliamentary absences by saying he could do politics from his boat – announced his resignation on Saturday, blaming a “media lynching”.

In his resignation letter, Andrea Mura said he had always taken his parliamentary mandate “with the greatest seriousness” but that he had been unfairly rounded on by the media with “ignominious and groundless accusations” which his Five Star Movement (M5S) had not given him the opportunity to explain.

Since his election in March, Mura had turned up for only eight of the assembly’s 220 votes, according to monitoring website OpenPolis.

The 2010 Italian Sailor of the Year, however, breezily rejected criticism last week, telling Sardinia’s La Nuova Sardegna newspaper: “Political activity is not only conducted in parliament. You can also do it on a boat.”

He added: “[With] the overwhelming majority of the Five Star MPs in the chamber of deputies, it makes no difference whether I am present or not.”

The staunch environmentalist said at the time he had always told his party that he saw himself as an “advocate of saving the ocean from plastic more than as a member of parliament”.