Struggling commodity prices and stronger sterling undermined the FTSE 100 as it nudged 0.1% lower to 7,105.
The blue-chip index bias towards overseas earnings saw it benefit from a weaker pound after the Brexit vote, although this trend reversed following UK Prime Minister Theresa May's shock decision to call a snap general election in June.
Brent crude oil slid 1% higher to $53.46 per barrel, while commodity prices slipped in the other direction.
Gold retreated 0.1% to $1,279 per ounce and copper fell 0.2% to $5,577 per tonne.
Cloud platform giant IBM was the biggest faller on the Dow Jones. The stock tumbled by nearly 5% on declining sales and dragged US stocks lower on Wednesday.
Asian markets didn't fare much better as indices in Japan and China were flat on Thursday.
The only exception was the Hang Seng in Hong Kong, which closed 1% higher as investors felt less uneasy about geopolitical tensions with North Korea.
FTSE 100 RISERS AND FALLERS
Ben & Jerry's owner Unilever (ULVR) boosted its turnover in its first quarter of 2017 by 6.1% to €13.3bn, and hiked its quarterly dividend on a confident outlook. Shares in the consumer colossus advanced 1.5% to €39.97.
Challenging weather conditions in Western Australia failed to bring Rio Tinto (RIO) down as the miner delivered solid production in the first quarter of 2017, but the stock was flat at £30.34.
More people tuned into NOW TV owner Sky (SKY) as recorded nine-month revenues jumped 11% in reported terms to £9.64bn thanks to growth in the UK, Ireland, Germany, Austria and Italy.
FTSE 250 RISERS AND FALLERS
Embattled Southern Rail operator Go-Ahead (GOG) maintained its full year expectations for its bus and rail divisions provided at its half year results in February. This was a relief for investors as the stock accelerated 3% to £17.81.
Asset manager Man Group (EMG) continued the upbeat trend in the sector as its assets under management rose 10% in its first quarter, prompting a 6% increase to 149.4p.
Investors were not thrilled with Debenhams (DEB) new CEO Sergio Bucher's plans to make the department stores a destination for 'social shopping'. Previously £350m was allocated to a turnaround plan out to 2020, but this cost was hiked by £100m. The stock fell 6% to 52p.
SMALL CAP RISERS AND FALLERS
Ortac Resources (OTC) agreed to form a joint venture with a Slovakian company to jointly develop the Sturec Gold Project at Kremnica. It was seen as a golden deal as the stock soared 24% to 3.8p.
A memorandum of understanding with Mbeya Cement to develop a strategic regional collaboration and supply of materials agreement boosted Kibo Mining (KIBO) by 2.6% to 5.2p.
UK-based Modern Water (MWG) sealed the sale of its proprietary forward osmosis technology for seawater desalination to Hangzhou Water Treatment Technology Development Center in China. Shares in the holding company sparked 20.5% to 11.9p.
Middle East hotel owner Action Hotels (AHCG) struggled despite management expecting to report rises in full year total revenue and earnings on top of solid trading in its first quarter of 2017.
The market was unhappy with Shearwater's (SWG) conditional agreement to take over software solutions provider SecurEnvoy for £20m as the stock was marked 9.5% lower to 4.3p.