Italian football clubs are ignoring the racist chanting of their supporters, it has been claimed.
Belgium striker Romelu Lukaku was subjected to monkey chants from the crowd during Inter Milan's win over Cagliari on September 1.
A section of hardcore Inter 'ultra' fans, known as 'Curva Nord', have insisted the abuse aimed at Lukaku by rival supporters were not meant to be racist.
Tobias Jones, author of a new book titled 'Ultra', told Sky Sports News: "In the balance for a football club between calling out the racism of the fans or turning a blind eye, I'm afraid they're almost always going to turn a blind eye."
Inter Milan say they maintain their fight against racism "every day" but would not comment on the statement from fans.
Last week, Italian police arrested 12 Juventus 'ultra' fan leaders for a series of alleged offences.
The accusations include making illegal demands to the club such as carrying out racist chants during matches if they were not given more tickets than the number allotted.
It is claimed clubs are vulnerable to alleged extortion.
"There's a law in Italy called objective responsibility," said Jones. "If there's racist chanting by the fans, the club gets fined and it will be 10, 20, 30 thousand euros.
"So, the ultras can say 'unless you give us fifty or a hundred free tickets', in which they get a mark-up of a lot of money, 'unless you give us these free tickets, we are going to make these racist noises and you are going to get fined'.
"It is a form of blackmail and that's one of the reasons they say, and I don't believe it, 'we're not racist, we're just doing this to put pressure on the club in order to get free tickets'."
Jones claims discriminatory behaviour from some ultras overshadows their charitable work.
"What's not seen is all the great stuff," says Jones. "Every time there's an earthquake in Italy, every time there's flooding, every time there's a medical emergency, the ultras are always on the front line. It's a fascinating contradictory movement."