a thorn in the side of #5
シンガポールの犯罪組織が、Ｊリーグのクラブ関係者に日本で接触を図ったが、不首尾に終わったことを「朝日新聞」が伝えてました。
以下は同じ内容の英文ですが、a thorn on the side of football leaguesが気になりました。
Investigator says J-League almost infiltrated by Singaporean match-fixing ring
An investigator that has been working with FIFA to investigate match-fixing scandals around the world says that a Singaporean crime syndicate tried to infiltrate the lucrative world of the J-League by contacting one of the clubs. Fortunately, the unnamed but powerful team refused to cooperate with the fixers.
Match-fixing has been a thorn on the side of football leagues all over the world, but so far, it has failed to Japan’s premier professional league. The investigator said that J-League matches has one of the highest online betting rates by bookmakers not just in the region but also in Southeast Asia. He said he will not be surprised if there will be a match-fixing scandal soon, especially as the league prepares to establish the J3 division, that will feature both amateur and professional players. According to his source, the syndicate moved on to China when they realized that it was difficult to establish a game-fixing scheme in Japan. This year, several match-fixing scandals were discovered in China’s professional league that has affected clubs, players and referees alike.
通常これはa thorn in one's side（flesh）ofで、「横腹にささったとげ」から「悩みの種、目の上のこぶ」という意味となります。
ここはサッカーの話なのでinをonに変えたと推測します。しかし聖書に由来する由緒あるイディオムなので、何度もチェックしておきましょうね。
ちなみにわたしも１９９６年に書いた論文のタイトルにこれを用いたことがあります（"A Thorn in the Side of ELT in Japan: Teaching of English Prosody,"『英語学論説資料』第28巻（英語教育）第5分冊, pp. 263-269. ）。（UG）
http://d.hatena.ne.jp/A30/20111219/1324265326
