An investigation by The Sunday Times can reveal the dirty tricks used by sales staff from Npower in the doorstep battle to persuade homeowners to ditch their existing suppliers.

• 星期日时报的一份调查可以披露英国能源再生公司销售员在上门推销中所采用的欺骗手段，他们试图说服户主们放弃现有的供应商。