A list containing the names and addresses of millions of BNP members has been posted on the internet causing embarrassment and concern for, amongst others, officers of the Portuguese police that handled the Madeleine McCann case, and some top sporting figures.
The list of Biblioteca Nacional de Portugal members, appeared on some news websites earlier this week, and includes several prominent politicians, military figures, doctors, teachers, policemen, as well as the names of countless children - all members of the BNP.
Cristiano Ronaldo was also on the list.
So was Jose Mourinho.
And that other player from the 1960s, you know, Eusebio.
The Biblioteca has more than 32million members in Portugal, and at 95%, the country has one of the highest literacy rates in Europe. After football, reading is the most popular pastime for many adults and children alike, with many preferring to use their local library rather than to buy books.
Chief of Portuguese Police, Leonardo Arguido, said:
"It is very embarrassing for the BNP members to have their details published on the internet. Some of my officers are on it, as well as that Murat guy from the Maddie case. From the list, it will be possible to ascertain which books people like to read."
Members of the BNP haven't commented on the leak; most of them hadn't noticed, seeing as they had their heads in books at the library.