The pound fell to a one-month low after Manchester Mayor Andy Burnham said he is seeking to run for Parliament, potentially opening an avenue to challenge embattled UK Prime Minister Keir Starmer.

Sterling traded as much as 0.7% lower at $1.3429, the weakest level since April 13, after Burnham’s announcement, which came after the gilt market closed. Labour Member of Parliament Josh Simons announced plans to step down from his seat to allow Burnham the opportunity to run.