The index <.FTSE> fell 1 percent, though it outperformed Europe's STOXX 600 and Germany's DAX, which dropped 2.1 percent.
The FTSE 100 fell despite a slide in sterling, which usually supports the exporter-heavy index. The negative rela
tionship between the two has evaporated recently.
Many UK-listed companies derive a significant chunk of revenues from emerging markets, and several Russian companies are listed on the British stock market.
Russian gold miner Evraz was the worst-performing FTSE 100 stock, down 8.8 percent after broker VTB Capital downgraded it and the rouble fell to its lowest since July 2016 on anxiety over a fresh round of U.S. sanctions.
Russia-exposed miners Polymetal and Kaz Minerals fell 2.4 and 1.4 percent.
Smaller UK-listed stocks exposed to Turkey and nearby emerging markets were also bruised.
DP Eurasia, a franchisee of Domino's Pizza which generates 68 percent of sales in Turkey, sank 14.4 percent to the bottom of the small-caps index <.FTSC>.
Travel operators On The Beach and Thomas Cook, which sell package holidays to Turkey, fell 4.1 percent and 1.9 percent respectively.
Georgian lenders TBC Bank brought up the rear on the FTSE 250, down 3.7 percent as the Georgian lari <GEL=> sold off.
Emerging markets-focused asset manager Ashmore tumbled 3.7 percent.
The Turkish lira's slide to record lows, as President Tayyip Erdogan dismissed investors' concerns, sent tremors across other emerging markets, with South Africa's rand falling to a six-week low.
This weighed on South Africa-exposed bank Investec, whose shares fell 3 percent. Packaging firm Mondi and miner Anglo American, also founded in South Africa, tumbled 2.3 and 2.6 percent.
Emerging markets-focused lender Standard Chartered fell 1.9 percent.
"Whilst generally EM economies are much stronger than they were 20 or 30 years ago you've still got some countries that are a bit of a mess," said Peter Elston, chief investment officer at Seneca Investment Managers.
"That's occasionally going to cause problems for the asset class as a whole, as it is doing at the moment."
Miners were a big weight on the FTSE 100, with Anglo American and Glencore falling 2.5 percent and 2.7 percent as copper prices fell on a stronger dollar.
Outside EM-driven moves, shares in engine maker Rolls-Royce fell 3.7 percent after JP Morgan downgraded the stock to "underweight".
"Relative to other civil aerospace stocks we follow, we think Rolls-Royce now offers investors a less attractive risk-reward," JPM analysts wrote, arguing the firm is showing deteriorating earnings quality.
The FTSE 250 <.FTMC> fell less sharply, down 0.7 percent thanks to its less internationally exposed constituents.
"Mid-caps fell horribly following the (Brexit) vote, and they've since made back everything they've lost and more, which suggests they have been able to thrive in this post-ref vote environment," said Seneca's Elston.
However, he added, "earnings have been very mixed."
Analysts have been cautious on mid-cap earnings, while the index has been declining since a record high hit on June 14.
(Reporting by Helen Reid and Julien Ponthus; editing by Andrew Roche)
By Helen Reid