LONDON: UK shares opened in negative territory on Wednesday as the United States threatened to slap 10 percent tariffs on a list of $200 billion worth of Chinese imports, escalating a trade war further and sending jitters across global markets.

The blue chip FTSE 100 index was down 1.35 percent at 7,588.08 points by 0820 GMT in line with other European markets, with losses across all sectors.

"Now nervously waiting for whatever China's retaliation will be - beyond the immediate criticism of the proposal by Beijing - the markets went into panic mode on Wednesday", wrote Connor Campbell, an analyst at Spreadex.

China's commerce ministry said on Wednesday it was "shocked" and would complain to the World Trade Organization, but did not immediately say how it would retaliate.

On the British political front, the pound was stable as analysts took the view it was likely Prime Minister Theresa May would hold on to power and limit the economic damage of leaving the European Union.

Royal Dutch Shell and BP took the most points off the British blue chip index, down 1.6 percent and 2.1 percent, as oil prices fell with investors fearing the trade dispute could depress global economic growth and reduce energy demand.

London-listed miners and commodities groups also weighed heavily with Rio Tinto, BHP Billiton down 2.7 and 2.9 percent.

Glencore fell 3.8 percent after it announced it had set up a board committee to oversee its response to U.S. demands for documents on its business in the Democratic Republic of Congo, Venezuela and Nigeria, as part of a corruption probe.

Online supermarket Ocado lost 6 percent, giving up some of its 9 percent gain from the previous session when its shares surged after publishing first-half earnings.

Among smaller companies, Indivior plummeted 33.6 percent after warning revenue and adjusted net income would come in below its forecast, hurt by the launch of generic versions of its bestselling opioid addiction treatment in the United States.