Frankie Dettori has been suspended from riding for six months after being found guilty of taking a prohibited substance, believed to be cocaine.
Dettori's legal representative Christopher Stewart-Moore said the Newmarket jockey "fully accepts" France Galop's decision to ban him for six months.
"France Galop have today announced their finding Frankie Dettori has committed a breach of their rules relating to prohibited substances," said Mr Stewart-Moore.
"I have spoken to Frankie since the announcement was made and he has told me he fully accepts France Galop's decision.
"He also accepts that he has let down the sport he loves and all those associated with it, as well as the wider public.
"But most of all, and this is his greatest regret, he has let down his wife and children."
Dettori, who was cautioned by police for possession of cocaine in 1993, has vowed to "rebuild his reputation" once he has served his suspension.
Stewart-Moore said: "He is enormously grateful for the opportunities that he has been given by owners and trainers over the years, and for the support of his many fans.
"Racing has been good to Frankie and he knows that his privileged position brings with it responsibility.
"For this reason he is determined to rebuild his reputation when he returns to the saddle.
"Frankie could make excuses. He has, after all, regularly been tested for prohibited substances throughout his career.
"He is clear, however, that the responsibility for his current situation lies squarely with him.
"From the start of France Galop's inquiry he has acknowledged to them he has made a mistake and that the fault was his.
"Finally, he has asked me to thank everyone for the many messages of support he and his family have received."