Investing.com - The British pound tumbled on Thursday, after UK Brexit Minister Dominic Raab resigned, adding to uncertainty over whether Prime Minister Theresa May's proposed Brexit deal will win parliamentary approval.
The pound sank to session lows on the news, with GBP/USD dropping more than 1% to 1.2853 by 4:05AM ET (0905GMT), pulling back from a high of 1.3071 on Wednesday.
The pound was also sharply lower against the euro, with EUR/GBP jumping 1.1% to 0.8804, well above the five-month lows of 0.8655 reached on Tuesday.
Raab, in a letter to the prime minister, said he cannot support terms of her draft Brexit plan.
"For my part, I cannot support the deal for two reasons," Raab said in his letter. "First, I believe that the regulatory regime proposed for Northern Ireland presents a very real threat to the integrity of the United Kingdom."
"Secondly," he added, "I cannot support an indefinite backstop arrangement, where the EU holds a veto over our ability to exit."