The pound continued to hover around 4-month lows Thursday after Prime Minister Theresa May suffered another cabinet resignation and faced intensifying calls by some members of her party to step down.
Sterling versus the U.S. dollar has moved toward the $1.25 handle, falling to a low of $1.2603 just as European trading began on Thursday.
Around the same time the euro bought 88.385 pence. The pound is currently on track to suffer 14 consecutive days of losses against the euro zone's common currency.
A fourth attempt by May to secure domestic support for her Brexit withdrawal plan looks doomed to fail and calls for her to step down have amplified.
Adding to May's troubles was the resignation of House of Commons leader Andrea Leadsom on Wednesday evening. Leadsom is the 36th minister to resign in the almost three years of the May premiership.
"Investors should not be complacent about the threat of a no-deal exit, which we believe would take the pound as low as $1.15 and 0.97 versus the euro," UBS analysts said in a note Thursday.
May is expected to depart in the next few days and her Conservative Party will narrow down candidates to two people before conducting a run-off vote.
A number of Conservative lawmakers are thought to be in the race to be the next U.K. leader, but bookmakers put the former Foreign Secretary Boris Johnson as favorite. Johnson confirmed his candidacy last week.
Johnson, a supporter of Brexit, has been hugely critical of May's attempts to agree a deal and has said that Britain has "nothing to fear" from leaving the trading bloc.
The investment bank J.P. Morgan said in a note Tuesday that a leadership victory for Johnson would likely trigger a number of defections from within the Conservative Party, strengthening the case for a general election.
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