UPDATE 2-FTSE ends 6-day losing run though earnings disappoint

* FTSE 100 up 0.4%, FTSE 250 up 0.5%

* Glencore slips after HY core profit misses market view

* Spirax-Sarco, Standard Life Aberdeen drop after results

* Investors seek shelter in safe-haven assets

* Upbeat earnings help mid-caps outperform (Adds news items, analyst comments, updates to closing prices)

By Shashwat Awasthi

Aug 7 (Reuters) - London's FTSE 100 snapped a six-day losing streak after a topsy-turvy session on Wednesday as investors composed themselves after sell-offs triggered by worries over the U.S.-China trade dispute and a weaker sterling supported exporter stocks.

Though poor earnings for global commodities trader Glencore and a handful of other companies limited gains, the main index ended 0.4% higher.

The mid-cap FTSE 250 rose 0.5%, helped by a post-earnings jump in Ultra Electronic and infrastructure products maker Hill & Smith.

The FTSE 100 has tumbled more than 5% in just a week, after having gained in six of the first seven months of the year, following President Donald Trump's threat to slap a 10% tariff on a further $300 billion in Chinese imports next month.

It had surged as much as 0.9% on Wednesday, but gave up a lot of those gains as a drop in yields spurred a global rally in safe-haven, fixed income assets and led investors to pile into bonds.

"There is a sense the recent bounce is on shaky grounds," CMC Markets analyst David Madden said. "The equity benchmarks in Europe that are higher, are showing small gains, and it doesn't exactly project an air of confidence."

In news-driven moves, Glencore weighed on the blue-chip index as it fell 2.5% and hit a near three-year low after an almost one-third drop in core profit.

Valve maker Spirax-Sarco slid 6.4% on its worst day in more than a decade after it warned sales growth at its main business would more than halve in the second half of the year.

Asset manager Standard Life Aberdeen gave up 7.5% despite an increase in first-half assets under management and administration.

Though traders refrained from dumping sterling, the currency remained subdued amid fears of a no-deal Brexit and its implications. Shares of internationally-focused companies such as Diageo, BAT and Unilever advanced.

On the mid-cap index, Hill & Smith surged 7.8%, while Ultra Electronics soared 11.4%, after both firms posted higher half-year results.

AIM-listed Burford Capital slumped 46% and shed roughly two billion pounds of its market capitalisation after short-seller Muddy Waters criticised the firm's accounts and took a short position in the fund. (Reporting by Shashwat Awasthi in Bengaluru; Editing by Patrick Graham, Anil D'Silva and Andrew Cawthorne)