England coach Steve McClaren has come under savage attack from his former Middlesbrough star Massimo Maccarone.
Maccarone, 27, launched his tirade in the Italian media after joining Siena.
He said: "The ever-smiling Steve 'The Magnificent' McClaren is the most two-faced and false person I've had the misfortune to meet in football."
Maccarone, signed by McClaren for £8m in 2002, added: "Only in England can someone with such evident limits become the head of the national team."
He told La Gazzetta dello Sport's official website,
"He disgusted me by leaving me on the bench for the 2004 League Cup final after having told everyone I was his number one and he was counting on me.
"At the end all he could do was mutter 'I know, I know'."
Maccarone, who made 102 appearances for Boro and scored 24 goals, also turned his fire on McClaren's successor at Middlesbrough, Gareth Southgate.
He said: "During the McClaren years, Southgate came to me endlessly, disguised as my friend, to give me support and encouragement, slating McClaren's treatment of me at every single opportunity.
606 DEBATE: Your reaction to Maccarone's comments
"When he became manager I was ready and excited by the fresh start that he promised me, but he conducted himself exactly as McClaren had done.
"I felt utterly betrayed by Southgate as he was the one who convinced me to stay and then promised me a run of five or six games which he never gave me."
But his attack shocked his representative Paolo Fabbri, who said: "I am really doubtful whether Massimo would be so rude as to criticise Steve McClaren and Gareth Southgate in this way.
"Yes, he was very upset not to play more often, any player would be, and yes, he might have specific points to make about McClaren and Southgate on a technical level - but I do not believe his frustrations go beyond that.
"It is said he didn't like Middlesbrough as a club, yet I know for an absolute fact that was not true because he was always very complimentary about the stadium and the training ground, the fans and the entire organisation.
"When he knows what is being said in his name, I am sure Massimo will be pretty upset because it is just not his style to be so rude and make comments of such a personal nature."