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* FTSE 100 down 0.4 pct
* Sky jumps as Comcast wins auction
* Randgold rises on Barrick Gold deal
* Thomas Cook sinks on profit outlook cut(Updates prices)
By Helen Reid
LONDON, Sept 24 (Reuters) - Resurgent fears of a protractedand costly trade war dented the FTSE 100 on Monday, while M&Astole the spotlight with Comcast finally clinching a takeover ofSky, and Randgold Resources agreeing a tie-up with Barrick Gold.
Britain's top stock index was down 0.4 percent asminers and consumer multinationals sold off.
Antofagasta, Glencore, Anglo American, Rio Tinto and BHP Billiton fell between0.3 and 2.6 percent as metals prices reversed course on theresurgence of trade worries.
London copper eased from a ten-week high as holidays inChina and Japan thinned trading.
Dealmaking drove some of the biggest moves. Europe's largestpay-TV group Sky soared after Comcast's offer won anauction for the company with a $40 billion bid.
Sky shares jumped 8.6 percent to 17.21 pounds, just belowComcast's cash offer of 17.28 pounds a share.
"The Comcast offer represented a 9 percent premium to theshare price close on Friday and more than double the 765p shareprice Sky had been trading at before the initial offer from Foxin December 2016," wrote Liberum analysts.
They added that they don't expect significant changes forSky. "It is very unlikely Comcast will look to rebrand Sky, ithas pledged to keep Sky News and there is visibility on themajor football contracts."
Randgold Resources shares jumped 6 percent after theminer agreed a deal with Canada's Barrick Gold tocreate the world's biggest gold miner.
"The larger scale will provide greater ability to grow,where the assets merit being developed," wrote Investecanalysts.
"In this regard the company will have a greaterpipeline of large development opportunities, whereasRandgold previously only had Massawa, an asset that many in themarket remained sceptical of," they added.
Among mid-caps, Thomas Cook Group lost nearly athird of its market value, down 28.1 percent at the bottom ofthe FTSE 250, after slashing its profit outlook, blaming aheatwave in northern Europe for a slower late holiday season.
Shore Capital analysts lowered their recommendation from"buy" to "hold".
"Assuming a more normal trading environment we would expectsome of this year's shortfall to be recovered, although thewinter is likely to be tougher," they wrote.
Thomas Cook peer TUI also fell 2.9 percent.
The FTSE 100, dominated by exporters which gain from aweaker currency, has been in the thrall of the pound recently asBrexit negotiations intensified. The currency's rise on Mondaykept the FTSE under pressure.
Sterling gained after UK Brexit Secretary Dominic Raab saidhe was confident Britain would eventually clinch a Brexit dealwith the EU.
Limiting losses on the index, however, were oil majors BPand Royal Dutch Shell. Crude prices rose to afour-year high after Saudi Arabia and Russia ruled out anyimmediate increase in production.(Reporting by Helen Reid and Danilo Masoni; Editing by MarkPotter and Andrew Heavens)
