LONDON — Andy Burnham looks set to take over as U.K. prime minister within weeks. One thing he won’t be able to ignore is Britain’s relationship with the EU. The U.K.’s outgoing leader, Keir Starmer, has spent the last year negotiating a series of agreements with Brussels. Burnham will be taking over mid-season. The agreements were due to be concluded at a summit on July 22 — a date that was put on the calendar just a week before Starmer suddenly announced his resignation. They include an agri-