The UK’s Mail Online sued Gawker on Thursday — claiming the embattled New York gossip blog libeled it in a scathing March 4 essay.

The essay, by James King, a former Mail Online freelancer, claimed the UK-based operation regularly stole articles from other news sources without proper attribution.

King claimed in the first-person March 4 piece entitled “My Year Ripping Off the Web With the Daily Mail Online” that his former employer routinely “plagiarized” articles, engaged in “dishonest practices” and took a “buccaneering approach to accuracy and intellectual property.”

But the Mail Online says in its Manhattan Supreme Court libel suit that King’s accusations are entirely false — and that Gawker knew that when it published the “exposé.”

The lawsuit states, “Indeed, and ironically, editors at The Mail had to repeatedly remind defendant King, who worked out of the Mail Online’s New York newsroom, of the need for proper attribution.”

On one occasion, editors caught King trying to plagiarize a New York Post article about a US armed unit in Iraq, the suit claims. The story was pulled.

King worked for Mail Online from May 2013 until July 2014. He had shopped his essay to the Washington Post, which declined to publish it after hearing from The Mail’s legal department that the story was incorrect, according to court papers.

“The Mail’s reputation, goodwill, and business have been damaged,” the suit says. The website is suing for unspecified damages.

King could not be reached for comment.

Gawker, through a spokesperson, said: “While we’re not surprised that the Daily Mail doesn’t like what James King had to say about his time working there, this baseless complaint doesn’t even attempt to refute the vast majority of the author’s detailed anecdotes about his experience as a Daily Mail writer.”