UK's top share index expected to open slightly lower after Brexit deal defeat

Britain's top share index was expected to open slightly lower on Wednesday after lawmakers defeated Prime Minister Theresa May's deal to leave the European Union by a crushing margin overnight, deepening political and market uncertainty. The FTSE 100 was seen opening 3 points lower and underperforming its European peers, according to financial spreadbetters at IG.

The small drop comes as sterling eked out small gains against the U.S. dollar in early dealings, with the sizable defeat for May seen forcing Britain to pursue different options, including a delay to the exit. Sterling rallied more than a cent from the day's lows against the dollar after the vote on Tuesday night. The blue-chips are often pressured by a stronger pound, as 70 percent of their income are generated overseas. Frankfurt's DAX is seen opening 36 points higher and Paris' CAC 40 will be flat, according to IG.

Parliament on Tuesday voted 432-202 against May's deal, the worst parliamentary defeat for a government in recent British history. Scores of her own lawmakers - both Brexiteers and supporters of EU membership - joined forces to vote down the deal. Recently, the FTSE 100 has moved in rare lockstep with the domestic currency, underscoring deepening worries about the fallout across Britain's financial markets and economy from the tumultuous negotiations for a Brexit deal. 

(With inputs from agencies.)