Britain's FTSE 100 fell sharply and the pound surged the most in three months after the country's High Court ruled that lawmakers must vote to trigger the clause that will launch its exit from the European Union.

The pound gained more than 1.1% against the U.S. dollar immediately following the ruling, its biggest one-day rise since August, to trade at 1.2441, the highest in nearly a month. The FTSE 100, however, which derives more than 75% of its revenue from outside the U.K., fell quickly in the aftermath of the decision, giving back earlier gains to trade 0.51% lower at 6812.3.  

However, U.K. bank stocks, which have suffered since the June 23 vote on concern that some would lose their ability to sell financial services into the eurozone, rose sharply, with Royal Bank of Scotland (RBS) - Get Report gaining 5.5%, Lloyds Banking (LYG) - Get Report adding 3.15% and Barclays (BCS) - Get Report advancing 2.8%. 

Broader European shares added to modest gains and were quoted marginally higher across the board after the High Court ruling. Sentiment, however, is still being held back by political risk concerns as narrow U.S. election polls overshadowed trading in Asia following the worst losing streak for the S&P 500 in over five years.

One of the more significant downside movers in early trading were shares of Credit Suisse (CS) - Get Report, which fell by around 4.9% in Zurich after the Swiss lender's CEO warned of "challenging" conditions in the months ahead.

Credit Suisse posted an unexpected Sfr41 million ($42.25 million) profit in the three months ending in September but set aside a further Sfr357 million to cover potential litigation, notably related to mortgage bond sales in the United States.

"Looking ahead, we expect market activity to continue to be influenced by geopolitical and macro-economic uncertainty over the next several quarters and the outlook to remain challenging," said CEO Tidjane Thiam. "We still have a long way to go in our journey but we are fully mobilized to deliver in challenging market conditions on our key commitments to reduce cost, strengthen our capital base and drive profitable business growth."

Germany's Adidas (ADDYY) was another notable decliner, falling 6.6% in early trading after the sportswear giant posted third-quarter earnings that were largely in line with analysts' estimates, but maintained its full-year guidance and said it would likely take a financial hit from its restructuring of its Reebok brand.

Adidas said basic earnings per share for the three months ending in September came in at €1.93, up 24% from the same period last year, taking net profit to €387 million ($430 million), modestly higher than the €377 million consensus.

Adidas shares were quoted at €136.85 by late morning in Frankfurt. 

Equity markets in Asia were kept on the back foot overnight amid news that U.S. presidential candidates Hillary Clinton and Donald Trump remain in a virtual dead heat in the final days of the grueling campaign. The Real Clear Politics website's poll tracker has Clinton holding a narrow 1.7 point lead, although that gap has consistently narrowed since the Federal Bureau of Investigation said last week that it was re-opening it probe into her use of a private email server while she was Secretary of State. 

U.S. stocks remained under pressure Wednesday as investors recalibrated their election bets and piled into safer assets across the board. The S&P 500 fell a further 0.25% in the session, extending its series of declines to the longest losing streak since 2011. 

The U.S. dollar took the brunt of the market's defensive tendencies, falling 0.33% against a basket of global currencies before rebounding to 97.20, despite clear signalling from the U.S. Federal Reserve that it is very likely to return to its rate "normalization" path at its next meeting in December.  

Global oil markets rebounded firmly, however, with traders picking up cheap prices after a sharp 3% decline late Wednesday following the U.S. Energy Information Agency's report that crude inventories rose by a record 14.4 million barrels in the week ending Oct. 28. Nymex light sweet crude prices were changing hands at $45.96, up 1%, by late morning in London.