Beijing has denounced a “thoroughly illegal” international tribunal that ruled against its expansive claims in the South China Sea, with a senior diplomat describing it as a “thorn” in the side of its relationship with the Philippines on the 10th anniversary of the decision. In an article published in People’s Daily on Sunday, Jing Quan, the ambassador to the Philippines, said clearing its “lingering toxic legacy” was a matter of the utmost urgency. “The most important task for Manila today…