Complex sentence: There are plans to build an underground pedestrian walkway to nearby Walthamstow Queens Road station, work on this commenced in October 2006 meaning that the main Underground ticket office will be closed until late 2007.
Split into simpler sentences: There are plans to build an undergroud pedestrian walkway to nearby Walthamstow Queens Road station, work on this commenced in October 2006. The main underground ticket office will be closed until late 2007.