OXFORD, England — The U.K.'s new Labour Prime Minister Keir Starmer is seeking to reset fractured relations with Europe on Thursday as he hosts more than 45 heads of state from across the continent at Winston Churchill's birthplace. Starmer will tell the European Political Summit that the challenges facing Europe cannot be confronted alone, and that the region must work together to present a united front on security and defense. "We cannot let the challenges of the recent past define our relationships of the future," Starmer said in a Wednesday statement from Downing Street. "That is why European security will be at the forefront of this government's foreign and defence priorities, and why I am focused on seizing this moment to renew our relationship with Europe