UPDATE 1-Defensive FTSE 100 ekes out a gain amid global trade sell-off

* FTSE 100 up 0.1 pct

* Trade tensions weigh on stocks

* WPP drops after co to probe CEO (Updates prices, adds details)

LONDON, April 4 (Reuters) - Britain's FTSE 100 managed a small gain on Wednesday despite global trade worries denting appetite for risky assets, as investors piled into defensive sectors which make up a large part of the UK index.

The blue-chip FTSE 100 closed 0.1 percent higher, while mid-caps fell 0.7 percent.

The FTSE recovered from sharp losses at the open, when it slid along with other European indexes after China announced additional tariffs on $50 billion of U.S. goods.

Worries over global trade have weighed on stocks over the past month, with the Trump administration set to unveil a list of Chinese advanced technology imports targeted for U.S. tariffs to punish Beijing over technology transfer policies.

"It's more (about) the second-order effects on global growth sentiment, and the fact that this is all arriving at a time where some of the leading indicators have been rolling over anyway," Ian Williams, economics & strategy research analyst at Peel Hunt, said.

The FTSE 100 was the only European index to end in positive territory, a feat investors put down to its strong weighting in defensive sectors less vulnerable in a sell-off.

"Generally, at times like this historically the UK equity market has been reasonably defensive ... the nature of the sector weightings tend to be a bit less cyclically-exposed," Williams added.

Pharmaceutical stocks Shire and GlaxoSmithKline were among the biggest gainers, while precious metals miner Fresnillo was up 1.1 percent, as gold is considered a safe-haven asset.

Cigarette firms British American Tobacco and Imperial Brands, and consumer goods giants Diageo and Unilever, also gained as investors rushed into high dividend-paying stocks.

Sectors which are more sensitive to the economic cycle, such as financials and materials, were the biggest weights.

Miners Anglo American, BHP Billiton, Glencore and Rio Tinto fell 2.5 to 3.2 percent as metals prices sank. Investors worried that tariffs may disrupt metal imports to China, the biggest global buyer.

Shares in WPP fell 2 percent after the advertising group said it was investigating an allegation of personal misconduct against its CEO, Martin Sorrell, who denied wrongdoing.

"Given (Sorrell's) high profile, the accusations are bound to attract a lot of attention and, given he is the face of WPP to many, there is likely to be a negative impact on sentiment today," Liberum analysts said.

"One thing this may do is intensify talk about Sir Martin's successor at WPP, which has been an issue lurking in the background," they added.

While individual stock moves were relatively muted, shares in Morrisons were the top gainers, up 2.9 percent after favourable data from Kantar on the supermarket's performance.

The data showed Morrison and peer Tesco continued to outperform rival "big four" supermarkets in the 12 weeks to March 25, with both enjoying sales growth of 2.4 percent. Shares in Tesco however declined 0.7 percent.

Among small-caps, Topps Tiles shares tumbled 13.3 percent to a four-month low after the flooring retailer said sales had been hit by a weaker market and bad weather. (Reporting by Kit Rees Editing by Robin Pomeroy)