A week of steady progress for global equities ended with a fizzle as the FTSE 100 closed down 0.4% to 6,918.18.
Early on the index had been as much as 0.6% higher. Sterling continued to enjoy strength on hopes of an extension to Article 50.
The S&P 500 was down 0.5% at 2,584.43 around 4.30pm UK time.
In corporate news, struggling regional carrier Flybe plunged 77% to 3.75p after it agreed to be taken over for a mere £2.2m by a joint venture comprising Stobart Group, Virgin Atlantic and funds managed by Cyrus Capital Partners.
The venture, dubbed Connect Airways, also offered a £20m bridge loan facility and up to £80m of further funding to support the airline's growth. But investors hoping a takeover battle would push up Flybe's share price have been left bitterly disappointed.
Stobart shares rallied 7.2% to 160.8p.
LARGE AND MID CAP RISERS AND FALLERS
Builder's merchant and DIY outfit Grafton, meanwhile, firmed 4.3% to 730p on announcing that it expected earnings 'slightly' ahead of the top end of analyst expectations.
Online electrical retailer AO World gained 1.8% to 126.4p after an 8.2% rise in third-quarter revenue helped it keep its full-year guidance intact.
SMALL CAP RISERS AND FALLERS
Online fashion retailer Quiz tumbled 32.5% to 24p as it downgraded its earnings and revenue guidance in the wake of a tough Christmas trading period and heavier spending on staff and marketing.
Mens' suit merchant Moss Brothers gained 1.5% to 26.6p as it reiterated it expected to post an annual loss as its margins shrank, while forecasting an 'extremely challenging' period ahead. Expectations were low heading into the announcement.
Management software provider Sopheon fell 6.4% to £12.50, even as it said 'early indications' pointed to it posting a higher-than-expected annual profit on the back of continue sales growth.
Legal services marketing business NAHL slumped 18.9% to 90p on announcing that it expected to post profits 5-10% below its previous expectations amid a 'disappointing' end to the year.