SHANGHAI (REUTERS) - A British Royal Navy warship that sailed close to islands in the South China Sea claimed by China risked hampering any talks about a free-trade agreement after Britain leaves the European Union, a major Chinese state-run newspaper said on Friday (Sept 7).

China and Britain agreed last month to look at the possibility of reaching a "top notch" post-Brexit free-trade deal which, if struck, would be an important political win for Britain's Conservative government.

"China and the UK had agreed to actively explore the possibility of discussing a free-trade agreement after Brexit. Any act that harms China's core interests will only put a spanner in the works," the state-run China Daily newspaper said in an English-language editorial.

Britain has long courted China for a post-Brexit trade deal and talked up a "golden era" in ties, although any talks cannot begin until Britain officially leaves the EU, and typically take many years to conclude.

The HMS Albion, a 22,000 ton amphibious warship, sailed near the Paracel Islands claimed by China last month, Reuters reported on Thursday, prompting an angry reaction from China, which called it a "provocation".

The Paracels are occupied entirely by China, but also claimed by Vietnam and Taiwan.

China's claims in the South China Sea, through which some $3 trillion of shipborne trade passes each year, are contested by Brunei, Malaysia, the Philippines, Taiwan and Vietnam. Britain does not have any territorial claims in the area.

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The China Daily said Britain was trying to "curry favour" with the United States, which has been pushing for more international participation in Freedom of Navigation Operations in the strategic waterways.

"Now that it is eyeing the US as an economic lifeline after it exits the European Union - the United Kingdom is no doubt eager to seize whatever opportunity it can to get into Washington's good books," the paper said.