United Pasokmomogun Kadazandusun Murut Organisation (Upko) deputy president Wilfred Bumburing, who has been rumoured to be ditching Barisan Nasional (BN) to join Parti Keadilan Rakyat (PKR) for quite some time, today resigned as BN chairperson for Tuaran amidst new speculation that a snap general election is likely to be called in September this year.