Read More...LONDON (AP) — London’s new mayor, a Labour Party member, is joining forces with Prime Minister David Cameron in the campaign to prevent a British exit from the European Union. Sadiq Khan is making joint campaign appearances Monday with Cameron, the Conservative Party leader who also favors remaining part of the 28-nation bloc. Campaigning is intensifying ahead of the June 23 in-out referendum with Cameron’s Conservatives badly split over the issue of Europe.