By Andy Silvester The Met Police is investigating an explosion that saw a ULEZ camera blown up in Sidcup last night. The controversial emissions policy sees high-polluting cars hit with a £12.50 charge for crossing the boundary into greater London. Reports of an explosion began circulating early this morning and just after 5pm the Met Police confirmed a criminal investigation was taking place. “The incident is being treated as a deliberate act, which was caused by what appears to be a low-sophistication improvised explosive device (IED),” the Met said. Counter-terror officers are leading the i…